For this analysis, we used annual totals of data from Pew Research Center telephone surveys among registered voters.
Overall, 34% of registered voters identify as independents, 33% as Democrats and 29% as Republicans.
Still, just 36% of registered voters have a four-year college degree or more education; a sizable majority (64%) have not completed college.
Today, Christians make up about half of Democratic voters (52%); in 2008, about three-quarters of Democrats (73%) were Christians.
The share of Democratic voters who are religiously unaffiliated has approximately doubled over this period (from 18% to 38%).