The government's Information Security Oversight Office has come out with its annual report, which means that we can now compare the classification and declassification numbers of Bush's first four years in office. If I was handier with computers, I'd present this in graphical form, but I'm guessing you can still detect the trend lines:
Number of documents classified by the Executive Branch, annually:
2001: 8.7 million
2002: 11.3 million
2003: 14.2 million
2004: 15.7 million
Number of documents declassified by the Executive Branch, annually:
2001: 100 million
2002: 44 million
2003: 43 million
2004: 28 million
At those rates the classification/declassification numbers should converge by, what, 2006? I guess we'll just have to trust 'em!
My take on Bush/Cheney/Rumsfeld secrecy, and its historical roots in the Gerald Ford presidency, here.
UPDATE: One graph, coming up! (Thanks to commenter rich.)
UPDATE 2: See comments for Clinton's poorly-trended second-term numbers as well.