In San Francisco and Marin counties, over half of the adult population has a college degree. An interactive graphic created by the Chronicle of Higher Education presents the percentage of the adult population with a college degree in every county around the country from 1940 to the present.
The interactive also allows for some filtering of the population, and somewhat predictably shows the counties with the highest percentage of college graduates concentrated in wealthy, high-population areas.
The Census bureau has released a few studies demonstrating the higher earnings college degree holders pull in. In a press release for a study released last year, the Bureau noted the following:
The data also demonstrate the extent to which having such a degree pays off: average earnings in 2008 totaled $83,144 for those with an advanced degree, compared with $58,613 for those with a bachelor's degree only. People whose highest level of attainment was a high school diploma had average earnings of $31,283.
The California counties with the lowest percentage of adults with a college degree are Kings, Lassen and Imperial.
|County||Bachelor's Degrees 2005-09||Median Household Income|
|Santa Clara County||43.9%||$85,569.00|
Source: College of Higher Education Interactive, U.S. Census Bureau American Community Survey 2005-2009
Click on any county in the interactive and you'll get more detailed information. Interestingly, the period from 1980 to 1990 is when San Francisco and Imperial counties really started gaining or losing college graduates as compared to the national average.
But that could be due to the limitations of the data, so be careful not to infer too much from the information.
In a blog post about the interactive, Nathan Yau of Flowing Data wrote, "There are some caveats with how Census has tracked educational attainment over the years (pre-1990 Census only asked number of college years completed rather than degree type) and changes in how people have been asked their race and ethnicity, but overall, the graphic is pretty good."
Chronicle of Higher EducationAdults with college degrees, by county.