Supporters chant 'four more years' as U.S. President Barack Obama addresses a campaign event at the Palm Beach County Convention Center September 9, 2012 in West Palm Beach, Florida. (Photo by Chip Somodevilla/Getty Images)

As President Obama and Mitt Romney’s contest has entered its final two months, the electoral map is becoming increasingly clear. And the black vote will matter in determining the winner.

A new report by the Joint Center for Political and Economic Studies, a Washington-based think tank, showed that 25 percent of Obama voters in Florida in 2008 were black, 20 percent in Michigan, 44 percent in North Carolina, 21 percent in Ohio, 22 percent in Pennsylvania and 35 percent in Virginia. The president needs to win at least two of those states in order to be reelected. (In Mississippi, a whopping 75 percent of Obama backers were black, but politics there are so racially polarized he won only 11 percent of the white vote).

Related: The demographic divide of 2012

Neither party expects a sizable number of African-Americans to switch from Obama to Romney. The president has approval ratings above 90 percent among blacks, and Romney’s campaign, aware of this fact, has made little effort to court black voters. Obama is likely to get 95 percent of whatever the black vote is, but the key question is how big is that part of the electoral pie.

The National Urban League estimated earlier this year that if black turnout dropped to 2004 levels, Obama would almost certainly lose North Carolina. (He won the state by 14,000 votes and an additional 127,000 black voters turned out in 2008 who were not there in 2004, according to NUL.) Such a drop would also severely complicate the president’s path in Ohio and Virginia.

Polls show black enthusiasm is sky-high, so there’s little reason to anticipate a substantial drop-off in the number of black voters. But expect to see prominent black supporters of the president, such as actress Kerry Washington, in these six states to fire up African-Americans, as well as some of the strongest fights over controversial voting provisions in these places. (It’s no accident the Obama campaign itself successfully filed suit in Ohio to make sure voters can cast ballots the three days before Election Day in the Buckeye State.)

Follow Perry on Twitter @perrybaconjr