[BohDaThone]

2008 was a bit over 131 000 000

See http://www.uselectionatlas.org/2008.php

[caveat emptor]

Here's the source where I got ~ 125 000 000 for 2008
http://www.infoplease.com/us/government/presidential-election-vote-summary.html

I used same source for 2000 and 2004 results.

The source you cited agreed with infoplease 2004 results, and had no comparable listing for 2000.