Obama has received at least 68,724,397 popular votes for the Presidency. I say “at least” because they’re still counting in California and several other states, and so Obama’s total should wind up comfortably over 69 million; 70 million appears unlikely, but is not entirely out of the question.
This total represents 22.62 percent of the Census Bureau’s 2008 estimate of United States population, which was 303,824,640. That figure doesn’t sound that impressive at first glance — fewer than one in four Americans actually voted for Barack Obama — but it’s actually the second-highest percentage ever, trailing only Ronald Reagan in 1984:
Details at FiveThirtyEight.com.