A Diverse and Changing Population

Growth in the region has rebounded from the housing market bubble and collapse that affected many parts of the Bay Area in 2007. The areas hit hardest were those towards the east and farthest from the San Francisco Bay. Those areas had seen housing prices more than double in just a few years prior to the crash. Although the entire region was affected by the subsequent recession, the core that formed the urban corridors around the San Francisco Bay is seeing a renaissance in population growth. The demographic mix of the population is changing in both predictable and less predictable ways, due to the aging of the baby boom generation, the influx of young adults drawn by a vibrant economy, and continued immigration to the region, especially from Asia and Latin America.

Gradual Growth in the Region’s Population

The population of the Bay Area has increased by 270,000 since 2010, reaching 7.4 million by 2014 according to the California Department of Finance (DOF). The annual population growth rate of the region in the recent four years (1.0 percent) is higher than the average rate during the first decade of the 2000s (0.5 percent) indicating the lasting attractiveness of the Bay Area to its residents as well as a rebound from the recession. Recent growth trends contrast with earlier periods and with the nation and California, as shown in Figure 3.1. Population growth in the region was slightly behind the rapid growth that occurred in the 1990s in California and the nation, and lagged well behind both state and region in the 2000s. Since 2010, population in the Bay Area has grown at a faster rate than in the US or California as a whole.

Figure 3.1 Average Annual Population Growth Rate

Source: ABAG from California Department of Finance Table E-5 and E-8 data

The overall regional trends hide significant shifts in where growth is occurring in the region, as seen in Figure 3.2. The fastest growing parts of the region were in the East Bay and North Bay in the 1990s. By the 2000s, the pace of growth had dropped sharply in all counties, but Contra Costa and Napa counties continued to outpace other counties. Since 2010, the more populated counties of Alameda, San Francisco, San Mateo, and Santa Clara have led the region in both rate and level of population growth, while in Sonoma and Napa counties, the pace of growth has slowed further.

Figure 3.2 Average Annual Population Growth Rate by County

Source: ABAG from California Department of Finance Table E-5 and E-8 data

Much of the new growth is in counties that also have the highest concentrations of jobs. Almost one-third of the region’s population increase occurred in Santa Clara County (32 percent), followed by Alameda County (23 percent). San Francisco, with a more constrained housing market, still accounted for 12 percent of the region’s population gain, while Contra Costa County, with less of the job growth but greater housing availability attracted 14 percent of the growth. Growth in Marin, Napa, Solano, and Sonoma counties has accounted together for less than 9 percent of the regional growth in total, compared to 17 percent between 2000 and 2010.

Between 2000 and 2010, the Bay Area added 140,300 households, reaching 2,606,300 by April 2010. During this time, Contra Costa County (9.1 percent), Solano County (8.7 percent) and Sonoma County (7.8 percent) had the highest ten-year growth rates in the region. Another 34,400 households were added in the region between April 2010 and January 2014. The three counties that had highest household growth rate from 2010 to 2014 were: Santa Clara (2.0 percent), Solano (1.5 percent) and Contra Costa (1.4 percent). The three counties which had the highest numeric increase were Santa Clara, Alameda, and Contra Costa. These three counties represent over two-thirds of all new households in the region. The shift of Santa Clara to the top spot in rate of growth is a further indicator of efforts of households seeking locations closer to jobs and the efforts of jurisdictions in the county to provide that housing, yet the slow rate of household growth overall signals that household formation continues to lag job and population growth. See Figure 3.3.

Although household formation has slowed in the current decade, household size has increased. Santa Clara County has the largest average household size of the nine Bay Area counties, passing Solano County in 2005 and steadily increasing since then, as shown in Figure 3.4. San Francisco’s household size was steady through 2010 but has begun rising as the city has become a residence of choice for the expanding young workforce. While most other counties also have seen an increase in household size, two North Bay counties, Sonoma and Solano, have 2013 household sizes equivalent to their 2005 levels.

Figure 3.3 Average Annual Household Growth Rate by County

Source: ABAG from California Department of Finance Table E-5 and E-8 data

Figure 3.4 Household Size by County (2005-2014)

Source: ABAG from California Department of Finance Table E-5 and E-8 data

The Aging of the Region

Consistent with nationwide trends, the population is aging. In 2013, the median age of the region was 38 (as estimated with PUMS data), compared to 37.7 in 2010 and 36.6 in 2000, as reported in the Bay Area Census website. The Bay Area’s population is older than California’s. Population 65 years old and over represented 12.7 percent of the total population in the region in 2013, compared to 11.8 percent of the state, and 13.4 percent of the nation. Population under 20 years old represented 24.4 percent of the region’s share, which is less than California at 27.5 percent and the United States at 26.6 percent. Each county has a higher median age than for the state as a whole. Marin County has the highest median age, while Santa Clara’s median age became the lowest among all counties in the region beginning in 2009, due to high shares of working aged population and children. Marin County’s population has aged particularly rapidly as seen in Figure 3.5. In contrast, San Francisco is the only county where the median age was lower in 2013 than in 2005.

Figure 3.5 Median Age, Bay Area Counties, California, and the United States (2005-2013)

Source: ABAG from US Bureau of the Census American Community Survey 1-Year Estimates, 2005-2013

With a changing age base, population growth since 2000 has been almost entirely in the age groups fifty and over, as shown in Figure 3.6. The 20 to 34 year age group, like other younger age groups, had dropped slightly in 2010 but began increasing again in the last three years, a sign of renewed job opportunities. The number under 20 grew sharply between 1990 and 2000 but has changed little in the past decade and a half.

Figure 3.6 Age Distribution over Time (1990, 2000, 2010 and 2013)

Source: ABAG from US Census 1980, Census 1990, Census 200 and American Community Survey 1-Year Estimates data

As of 2013, Marin County has the highest percentage of population over 50, as shown in Figure 3.7. Santa Clara and Alameda counties have the smallest percentage of population 65 years old and over. San Francisco has the largest portion of population between 20 and 29 years old (28 percent), and the smallest portion of population under 20 years old (15 percent). The share of population under 20 for all other counties was between 24 percent and 27 percent in 2013. Growth in the elderly population has been particularly high in Marin County Only in San Francisco is the share of population 65 and over lower in 2013 than in 2005. See Figure 3.8.

Figure 3.7 Age Distribution by County (2013)

Source: ABAG from US Bureau of the Census American Community Survey 1-Year Estimates

Figure 3.8 Percentage of Population 65 and Over by County (2005-2013)

Source: ABAG from US Bureau of the Census American Community Survey 1-Year Estimates

Demographic Shifts in Ethnic Composition

As the region grows, it continues to become more diverse. The non-Hispanic white population represented 52 percent of the total population in 2000, but the share had dropped to 41 percent by 2013 (Figure 3.9). Nevertheless, this group grew by 28,000 between 2010 and 2013, after shrinking in population size during the previous two decades. The non-Hispanic African American population represented 6 percent of the region’s population in 2013, down from 7 percent in 2010. In contrast, the Hispanic population and non-Hispanic Asian each accounted for 24 percent of the total population, experiencing growth rates of 5 percent and 9 percent, respectively, between 2010 and 2013.

Figure 3.9 Ethnic Composition of the Bay Area

Source: ABAG from US Census 1980, Census 1990, Census 200 and American Community Survey 1-Year Estimates data

The average annual growth rate for the region by ethnic group shows continued strong growth for Asians and Latinos since 2000. The two other major race groups (non-Hispanic white and non-Hispanic black) showed some decrease in its share of the total population between 2000 and 2013, with the majority of the population leaving between 2000 and 2005. See Figure 3.10.

Figure 3.10 Average Annual Growth Rate by Ethnic Group (2000-2005, 2005-2010, 2010-2013)

Source: ABAG from US Census and American Community Survey data
NOTE: Non-Hispanic Other is not included in this chart because the volatile changes may be due to shifting definitions rather than overall trends.

Between 2010 and 2013, Solano County has the highest growth rate in Hispanic population (8 percent), followed by Contra Costa County (7 percent) and Napa and Sonoma counties (6 percent). San Francisco County, with an increase of approximately 9,000 people, has the highest percent increase in non-Hispanic white population (3 percent), and Alameda County ranked second highest, increasing by 8,300 people, or 2 percent from the 2010 non-Hispanic white population level. For the non-Hispanic African American population, Napa County has the highest growth rate (21 percent), followed by Santa Clara County (10 percent), while Marin County lost 15 percent of the 2010 non-Hispanic African American population. Six of the nine counties have a 9 percent or more increase in non-Hispanic Asian population from 2010 to 2013, and among them, Napa County ranked highest (15 percent), followed by Marin County (13 percent) and San Mateo County (11 percent).

As of 2013, Napa has the largest percentage of Hispanic population (33 percent); Marin has the largest percentage of non-Hispanic white population (72 percent); Solano has the highest percentage of non-Hispanic African American population (14 percent); and San Francisco and Santa Clara County have the highest percentage of non-Hispanic Asian population (33 percent). Figure 3.11 shows the full distribution of population by ethnic group in 2013.

Figure 3.11 Ethnic Composition of Population in Bay Area Counties (2013)

Source: ABAG from US Census and American Community Survey data

Shifting Migration Patterns Reflect Changing Economy

International migration has played a significant role in the growing ethnic diversity and economic dynamism of the region. Regionwide, 30.2 percent of the 2013 population was foreign born, up from 27.4 percent in 2000 and 30.1 percent in 2010. The region has among the largest shares of immigrants in its population nationwide, yet the proportions still vary widely among counties as shown in Figure 3.12. The larger counties of Alameda, San Francisco, San Mateo and Santa Clara have a greater percentage of foreign born—between 31 percent (Alameda) and 38 percent (Santa Clara). The other five Bay Area counties have foreign born populations ranging from 17 percent in Sonoma to 24 percent in Napa.

Figure 3.12 Foreign Born by County (2000, 2005, 2010-13)

Source: ABAG from US Census and American Community Survey data

In any one year, a small share of new residents arrive from abroad. On average (since 2010) 84 percent the population remains in the same house they were living in the year before, while approximately 15 percent lived elsewhere (the remaining 1-2 percent are newborns). Of those who move, most remain in the same county. Figure 3.13 gives an overview of the close to 800,000 people who moved into their current unit in the past year. A little over 1 in 5 (roughly 4 percent of the total population) came from outside the region. By comparison, 17 percent of movers left the region. In other words, in the 2011 to 2013 period, there was a net migration gain relative to the rest of the country.

Newcomers to the Bay Area go mostly to Santa Clara (28%), Alameda (21%), San Francisco (16%) and Contra Costa (11%) counties, or 71 percent of newcomers (these counties for comparison have 76 percent of the population). Seven or fewer percent of movers from outside the region settle in each of the remaining five counties. Most movers pick a house in the same county, although with substantial regional variation. The share for Alameda, Contra Costa, Santa Clara, Solano and Napa counties is about two thirds. The county where most movers stay is Sonoma (74%), while Marin and San Francisco only see 58% and 51% of their relocating residents pick a new address in the same county. In contrast, since 2010, about three percent of the population has left the region annually, with Marin having the highest share of movers leaving the region rather than relocating in the Bay Area.

Figure 3.13 Bay Area Moves: Where From? Where to? (2011-2013)

Source: ABAG from US Bureau of the Census American Community Survey PUMS data, 1-year releases, 2011-2013
Note: Chart made adapting NPashaP’s BiPartite code

The numbers moving in and out of the region varies over time, as shown in Figures 3.14 and 3.15. More people moved to the Bay Area from outside the region in 2011 through 2013 than in the preceding three years for all counties. In four counties, this inward flow was higher than even at the peak of the housing bubble, with the absolute increase greatest in San Francisco and Santa Clara counties. These increased inward flows are matched by decreased outward flows. The numbers of previous residents who had left the region in the past year, annually between 2011 and 2013, has dropped relative to both of the previous economic boom and bust periods in San Francisco, Santa Clara, Alameda, Contra Costa, Solano and Sonoma counties. Only Marin and San Mateo had more people leaving the region in 2011 through 2013 than in either of the previous 3-year periods of 2005-2007 and 2008-2010.

Figure 3.14 Persons who Moved into the Bay Area in the Past Year (by County, 2005-2007, 2008-2010, 2011-2013)

Source: ABAG from US Bureau of the Census American Community Survey PUMS data, 1-year releases, 2005-2013

Figure 3.15 Persons who Moved out of the Bay Area in the Past Year (by County, 2005-2007, 2008-2010, 2011-2013)

Source: ABAG from US Bureau of the Census American Community Survey PUMS data, 1-year releases, 2005-2013

Geographic Manifestations of Changing Demographics

Given the amount of new businesses and employment growth in the South Bay, it is not surprising that San Jose has accommodated more of the region’s population growth than any other Bay Area city since 2000. Between 2010 and 2014, San Jose accounted for roughly 20 percent of the region’s population growth, a number that increased from 14 percent between 2000 and 2010. San Francisco accounted for 8 percent from 2000 and 2010, and 12 percent in the last four years, respectively. Oakland — which lost nearly 9,000 residents between 2000 and 2010 — has rebounded and added over 5 percent of the region’s population growth since 2010. The three largest cities in the region combined for one-third of the growth.

Population growth and the composition of that growth are closely tied to household formation and will influence the amount and location of housing demand in the region. The next section tracks trends in the region’s housing, affordability, and geographic location patterns.