Turnout was good, actually, when you include absentee ballots:

Michael McDonald, a professor and voting expert at George Mason University, estimated the popular vote total would reach133.3 million, after hundreds of thousands of absentee and provisional ballots that are still outstanding are finally counted, eclipsing the roughly 123 million voters who turned out in 2004. Mr. McDonald said there may be nearly a half million outstanding ballots in Georgia alone, and thousands more in other states — including the one with the largest turnout, California — that are still being counted.

Based on early figures, Mr. McDonald projected about 62.5 percent of all eligible voters cast ballots, just shy of the 62.6 percent figure that was recorded in the 1964 election. But that figure could very well rise as the remaining votes are finally counted.