Washington  - John McCain's wife, Cindy, heiress to a beer distributor in Arizona, earned more than 6 million dollars in 2006, according to a portion of her tax return released by the Republican presidential hopeful's campaign on Friday.

It was the first tax release ever by Cindy McCain, who in the past had said she would never publicly reveal her tax returns.

John McCain has regularly released his own returns separately, reporting earnings of 740,000 dollars over the past two years, mostly from salary as a senator representing Arizona and about one quarter through royalties from his five books.

Cindy McCain had been pressured to release her returns in order to fully disclose the family's financial picture. McCain's potential Democratic opponents for the November general election had released their joint returns earlier this year.

Hillary and Bill Clinton reported more than 109 million dollars in earnings over the past seven years, while Barack and Michelle Obama reported income of nearly 4 million dollars from 2000-2006, largely through royalties from Obama's own two books, Dreams From My Father and The Audacity of Hope.

The McCains have filed separate tax returns throughout their 27- year marriage - John McCain's second - as part of a prenuptial agreement. The campaign said Cindy McCain had yet to file for 2007 and would release the return when it was completed. (dpa)