NEW YORK (CNN/Money) - Federal Reserve Chairman Alan Greenspan has sharply increased his visits with White House officials since the start of the Bush administration, according to published reports.

The Washington Post, citing the work of academic researcher Kenneth Thomas, which appeared earlier in the trade publication American Banker, reported Thursday that Greenspan met with White House officials an average of three times a year from 1996 to 2000.

Since Bush took office in early 2001, Greenspan has met with White House officials an average of 44 times a year. He has already met with White House officials 12 times in 2004.

The Federal Reserve is independent from the executive branch. Fed chairmen have been careful to "avoid deals or the appearance of deals," with the White House in the past, said Donald Kettl, a political science professor at the University of Wisconsin and author of a book about political influences on the Fed.

Kettl told the post that Greenspan's meetings with current administration officials mark a "huge and historic shift," for a Fed chairman.

Thomas, a lecturer in finance at the Wharton School at the University of Pennsylvania who obtained the records of the visits with a freedom of information filing, praised Greenspan's performance as Fed chairman under Bush. But he noted that Greenspan provided important support for Bush tax cuts and now advocates making the cuts permanent. At one time he was critical of the effect the tax cuts would have on the federal deficit.

YOUR E-MAIL ALERTS White House Federal Reserve Taxation Financial and Business Services or Create your own Manage alerts | What is this?

"There's the appearance that (Greenspan) might not just be affected by economic winds, but possibly by political winds," Thomas told the Post.

Among the administration officials who met with Greenspan on his White House visits were Vice President Dick Cheney, with whom he met at least 17 times, Defense Secretary Donald Rumsfeld, with whom he met at least 11 times, National Security Advisor Condoleeza Rice, at least 12 meetings, and White House Chief of Staff Andrew Card, at least six meetings.

Greenspan met less frequently with Treasury Department officials during the Bush administration -- about 45 times a year -- than he did in the last five years of the Clinton administration, when he met with Treasury officials an average of 55 times a year, according to the report.