Numerator: Medical Board of California, Annual Reports (2007-2008, 2008-2009, 2009-2010, 2010-2011, 2011-2012, 2012-2013, 2013-2014, 2014-2015, 2015-2016,2016-2017).
http://www.mbc.ca.gov/Publications/Annual_Reports/
Denominator: U.S. Census Bureau, American Community Survey 1-Year Summary Estimates (2007-2017), Table B01001.
https://factfinder.census.gov/bkmk/table/1.0/en/ACS/17_1YR/B01001/0100000US|0400000US06|0500000US06071