The phenomenon was evident as early as the Iowa caucuses, and it proved to be a trend by Super Tuesday, but now that primary season is over, it's official: Young voters turned out in record numbers, casting a 6.5 million votes. This year's percentage of young voters was nearly double the turnout in 2000 (in the states that collected youth-voting data that year), according to figures compiled by the Center for Information & Research on Civic Learning & Engagement (CIRCLE).

The combination of a hotly contested Democratic primary between Senators Hillary Clinton and Barack Obama and the from-the-depths surge to the top by Senator John McCain no doubt helped increase interest in the race among voters under age 30. The more than 6 million votes cast is a dramatic increase in youth-voter turnout compared to the 2000 election and marks the first time the youth vote has risen in three consecutive election cycles since the voting age was lowered to 18 in 1971, according to CIRCLE.

"This primary season, the Millennials have gone to the polls in record numbers, showing they are an influential voting bloc in American politics," CIRCLE director Peter Levine said. "They realize what's at stake and the impact this election will have on their future and the future of our country."

Compared to 2000, when 9 percent of youth voters cast ballots in the primaries, in 2008, national youth-voter turnout was 17 percent (CIRCLE could not compare the vote in all states because many states did not do exit polling on youth voting in 2000 and 2004). In a sign of how the youth vote was up across the board, of the 17 states in which exit polls were conducted in 2000, 16 had increases in youth vote, with some seeing a tripling or quadrupling of numbers.

Among young Democrats, Obama was the candidate of choice, raking in the support of 60 percent of young voters overall and a majority in 32 of the 40 states. On the Republican side, though, the picture was less clear, with McCain (34 percent) barely edging out former Arkansas Governor Mike Huckabee (31 percent) and former Massachusetts Governor Mitt Romney (25 percent).

The numbers fit with national focus-group figures CIRCLE collected last fall, in which college students said they were deeply concerned about issues and ready to consider voting, as long as political leaders kept it on a positive tip and addressed real problems.

What do these numbers mean for the general election, now that the excitement over primaries has cooled?

"All key indicators and trends point to a predicted record turnout of young people voting this coming November," Levine said. "Now it's up to the candidates to run campaigns that address the real issues and concerns that young Americans care about, rather than the negative mudslinging tactics that have turned off young voters in the past."