As of right now, President Obama leads in the popular vote by ~2.8 million and has 60.4 million votes. When it's all said and done, he will likely exceed 65 million and lead by more than 4 million, or more than 3%. See why below the fold.
State 2012 2008 % Change Vote Change
Alabama 2,064,599 2,101,123 -1.74% (36,524)
Alaska 218,646 327,341 -33.21% (108,695)
Arizona 1,642,526 2,320,951 -29.23% (678,425)
Arkansas 1,057,302 1,088,936 -2.91% (31,634)
California 9,402,298 13,743,177 -31.59% (4,340,879)
Colorado 2,405,736 2,418,104 -0.51% (12,368)
Connecticut 1,507,467 1,649,589 -8.62% (142,122)
Delaware 413,844 412,412 0.35% 1,432
District of Columbia 243,348 266,871 -8.81% (23,523)
Florida 8,300,037 8,456,310 -1.85% (156,273)
Georgia 3,845,679 3,934,074 -2.25% (88,395)
Hawaii 429,494 456,064 -5.83% (26,570)
Idaho 649,653 663,119 -2.03% (13,466)
Illinois 5,091,061 5,578,195 -8.73% (487,134)
Indiana 2,595,024 2,773,343 -6.43% (178,319)
Iowa 1,563,943 1,540,646 1.51% 23,297
Kansas 1,127,560 1,242,195 -9.23% (114,635)
Kentucky 1,796,807 1,832,109 -1.93% (35,302)
Louisiana 1,988,576 1,960,739 1.42% 27,837
Maine 667,388 746,313 -10.58% (78,925)
Maryland 2,472,028 2,647,933 -6.64% (175,905)
Massachusetts 3,128,134 3,050,675 2.54% 77,459
Michigan 4,606,138 5,039,080 -8.59% (432,942)
Minnesota 2,915,694 2,912,071 0.12% 3,623
Mississippi 1,200,397 1,289,864 -6.94% (89,467)
Missouri 2,744,935 2,936,633 -6.53% (191,698)
Montana 454,946 493,097 -7.74% (38,151)
Nebraska 765,083 811,923 -5.77% (46,840)
Nevada 1,011,105 969,831 4.26% 41,274
New Hampshire 698,983 707,611 -1.22% (8,628)
New Jersey 3,315,546 3,909,041 -15.18% (593,495)
New Mexico 770,588 830,979 -7.27% (60,391)
New York 6,158,084 7,674,784 -19.76% (1,516,700)
North Carolina 4,494,682 4,324,212 3.94% 170,470
North Dakota 319,825 318,179 0.52% 1,646
Ohio 5,349,918 5,771,684 -7.31% (421,766)
Oklahoma 1,332,019 1,464,941 -9.07% (132,922)
Oregon 1,540,078 1,840,779 -16.34% (300,701)
Pennsylvania 5,589,084 6,046,231 -7.56% (457,147)
Rhode Island 417,448 469,538 -11.09% (52,090)
South Carolina 1,880,549 1,939,244 -3.03% (58,695)
South Dakota 363,688 382,764 -4.98% (19,076)
Tennessee 2,438,431 2,616,566 -6.81% (178,135)
Texas 7,962,799 8,145,632 -2.24% (182,833)
Utah 920,384 971,185 -5.23% (50,801)
Vermont 298,139 327,350 -8.92% (29,211)
Virginia 3,704,181 3,735,475 -0.84% (31,294)
Washington 1,920,323 3,071,587 -37.48% (1,151,264)
West Virginia 661,703 716,501 -7.65% (54,798)
Wisconsin 3,055,659 2,979,357 2.56% 76,302
Wyoming 245,785 255,534 -3.82% (9,749)
It may be ugly, but you can see that there are a lot of states that are down from 2008 to 2012 in total votes, some by quite a bunch. California is down 31%, or more than 4 million. While it may not reach 2008 levels, you can bet it's going to be at least 13 million. If we assume no states drop by more than 5%, we still have 8.2 million votes left to count, and I would guess we see most states closer to even than down. If we assume none drop by more than 3%, then it's 10 million votes. Even assuming a 50/50 split (won't happen since the biggest drops are in CA/NY/WA), Obama ends up with 65-66 million. Considering everything that has happened the last 4 years, a drop in support of 3-4 million is really a pretty strong showing!