The figure represent 17.4 percent of his $39.8 million in taxable income, a percentage he has repeatedly said is too low compared to what his own staff pays.Buffett caused an uproar in August when he said the wealthy should be subject to a higher rate of tax. The White House has co-opted his call into a “Buffett Rule” that would raise levies on the richest people.Following Buffett’s suggestion, Republican congressman Tim Huelskamp of Kansas sent the “Oracle of Omaha” a letter in late September calling on him to release his tax returns.Huelskamp sent Buffett a second letter reiterating the request earlier this month, and promising to release his own returns if Buffett would as well.Buffett, the chief executive of the conglomerate Berkshire Hathaway, responded in kind on Tuesday, according to a copy of the letter. Buffett did not release his full return, though, as many have called for him to do.In the letter, Buffett reiterated what he saw as the inequality of his paying a rate in the teens when most people who work for him pay a rate in the 30 percent range.But what he told Huelskamp he also wanted was for other ultra-wealthy Americans to release their own returns — in full, rather than the limited data Buffett himself shared.”If you could get other ultra rich Americans to publish their returns along with mine, that would be very useful to the tax dialogue and intelligent reform,” Buffett said. “I stand ready and willing - indeed eager - to participate in this exercise.”Buffett went on to suggest a method to get reticent moguls to release their returns, among them Rupert Murdoch, whom he has repeatedly challenged on the subject.”Having the ‘favored 400’ make their tax returns public - even if only code letters were attached to the various returns - would be a big step in informing legislators and the public of what needs to be done,” Buffett wrote.Huelskamp, in a statement Wednesday, slammed Buffett’s letter as inadequate and again called on him to either release his full returns or voluntarily give more tax money to the federal government.”Mr. Buffett still refuses to release his tax returns. What he does disclose may be accurate, but it is incomplete and it fails to explain how he shelters millions of dollars in income from taxation,” Huelskamp said.