Hello, Heterogeneity
Between 1948, when American National Election Studies first surveyed the electorate, and 1970, the percentage of voters who were white didn’t change much, ranging from 89 to 91 percent.
ANES didn’t begin breaking out data on mainline and evangelical Protestants until 1960. Traditional mainline Protestants – including Episcopalians, Presbyterians, Methodists and Lutherans — constituted a decisive plurality of the electorate at 45 percent. Evangelicals stood at 29 percent and Catholics at 20 percent. Only one percent defined their religion as “none.”
By 2008, whites had fallen to 74 percent of the electorate. The following chart, produced by Alan Abramowitz, a political scientist at Emory, shows the minority (“other non-white” and “black”) share of the vote from 1992 (13 percent) to 2008 (26 percent), with an estimate for 2020 (34 percent).
In a study published in February 2008, the Pew Forum on Religious and Public Life found that mainline Protestants, once the dominant force not only in politics but in the national culture, had fallen to 18.1 percent of the electorate, behind both Protestant evangelicals and Catholics – and barely ahead of the fast-growing category of “unaffiliated,” which reached 16.1 percent.
http://campaignstops.blogs.nytimes.com/2012/06/04/hello-heterogeneity/?nl=todaysheadlines&emc=edit_th_20120604
