The 2012 election produced another demographic milestone in the changing face of the nation as African Americans voted at a higher rate than whites for the first time, according to a Census Bureau report released Wednesday.

The report provided fresh evidence of how higher turnout rates among African Americans and a rapidly growing Hispanic population continue to reshape the electorate in presidential elections, with broad implications for the competition between the Republican and Democratic parties.

The report found that both blacks and Hispanics voted in higher raw numbers in 2012 than in 2008, helping to propel President Obama to a reelection victory over Republican Mitt Romney. The total number of white voters actually decreased between 2008 and 2012, the first such drop by any group within the population since the bureau started to issue such statistics in 1996.

Changing demographics continue to shrink the white share of the overall electorate in presidential years. Between 1996 and 2012, the white share of the total electorate has declined from almost 83 percent to 74 percent, according to the report, which is based on a post-election survey.

These demographic shifts have given Democrats an advantage over Republicans in presidential elections due to the GOP’s heavy dependence on white voters and the Democrats’ success in capturing sizable majorities among blacks, Hispanics and Asian Americans.

In last year's presidential election, blacks edge whites in voting. (The Washington Post/Source: Census Bureau)

Obama won just 39 percent of the white vote last November, according to exit polls. His deficit among whites was the largest for any winning Democratic candidate, but he prevailed by capturing 80 percent of the non-white vote.

Romney’s campaign assumed that black turnout would not match the levels of Obama’s first campaign in 2008, due to the historic nature of that election. Instead, African Americans turned out in bigger numbers and at a higher rate than ever last November, helping to swing the election to Obama.

In terms of participation rates, the Census survey said that 66 percent of eligible black voters turned out last November, compared to 64 percent of eligible white voters. In the course of three presidential elections, from 2004 to 2012, black participation has gone from seven points lower than white participation to two points higher.

Voting rates among Hispanics and among Asian Americans continue to be far lower than for whites and blacks. In 2012, only about 48 percent of eligible Hispanics and eligible Asian Americans turned out on election day.

Although the actual number of Hispanic voters increased in 2012, the Pew Research Center estimated that, because of low participation rates, about 12 million eligible Hispanics did not vote. These findings highlight the unmet potential of the nation’s fastest-growing minority group.

The survey found that the total number of voters increased only marginally between 2008 and 2012, after significant increases in the previous two cycles. An estimated 1.7 million more African Americans voted in 2012 than in 2008, while an additional 1.4 million Hispanics turned out to vote. White turnout declined by about 2 million.

But the participation rate — the percentage of eligible voters who actually turned out — was lower in 2012 than in the previous two elections.

If Obama was successful in turning out the African American vote in higher numbers and higher percentages, he fell short in doing the same among younger voters. The Census report notes that 2012 was marked by “large decreases in youth voting rates for all race groups and Hispanics.” Voting rates dropped by about 7 percentage points among both whites and blacks ages 18 to 24, and by almost 5 points among young Hispanics.

Women continued to vote at higher rates than men in 2012, as they have consistently in past elections. Among the overall electorate, women outpaced men by about 4 percentage points. Among African Americans, the gender gap was almost 9 percentage points.

William Frey, a demographer with the Brookings Institution, said the 2012 election was a landmark in American politics because of historic barriers to voting by African Americans and because of what he called quasi-legal efforts in some states that critics said were designed to make it more difficult for minority and lower-income voters to turn out.

“They persevered,” he said of African American voters. “This is an important time for them. They made their mark. They were very much responsible for reelecting Barack Obama.”

The Census data show how the combination of black turnout and declines in white turnout helped Obama win battlegrounds such as Ohio, Virginia and Florida. Ohio is a particularly interesting case study in the changing voting patterns among different population groups.

Eight years ago, white and blacks in Ohio voted at about the same rate, with 67 percent of eligible African Americans turning out and 66 percent of eligible whites voting. Four years later, the participation rate for whites dropped to 65 percent while the rate for blacks rose to 70 percent. Last November the turnout rate among whites fell to 62 percent, while the rate for blacks ticked up to 72 percent.

Over the past three presidential elections, black voting rates increased in Mississippi from 66 to 82 percent; in North Carolina from 64 to 80 percent; in New York from 54 to 69; in Virginia from 52 to 67 percent; and in the District from 64 to 77 percent.

There are caveats to the data, however. One is whether a white Democratic presidential nominee can attract African American votes in future elections at the same levels as Obama did in 2012. The second is whether Republicans can increase their share of the Hispanic vote. For now, Republicans aren’t likely to do any better among whites than they did last year and remain at a huge disadvantage among African Americans, making the Hispanic community a top priority of GOP leaders.

Carol Morello contributed to this report.

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