WASHINGTON, USA (AFP) — Republican presidential nominee Mitt Romney paid US$1.9 million in taxes on income of US$13.6 million in 2011, an effective rate of 14.1 per cent, his campaign said, citing returns filed yesterday.

The campaign also promised to release a summary showing that the Romneys paid taxes for each year between 1990 and 2009 at an average effective rate of 20.2 per cent, and that the lowest tax rate during that period was 13.6 per cent.

Romney, former governor of Massachusetts and a multimillionaire former private equity investor, has faced severe criticism throughout the race for refusing to release more tax data.

Democrats have sought to brand him a vastly wealthy plutocrat who is out of touch with everyday Americans and too secretive about his own taxes.

He released his 2010 tax returns, and promised he would do the same with 2011 before his October filing deadline, but he has repeatedly stressed he was not likely to release full tax data for years prior to 2010.

The latest filing, as well as the 20-year summary conducted and notarised by PricewaterhouseCoopers, will be available for public view online at 3:00 pm (1900 GMT) at the website www.mittromney.com/disclosure.

In addition, Brad Malt, the trustee of the Romney's blind trust, said in a blog post that "the Romneys donated US$4,020,772 to charity in 2011, amounting to nearly 30 per cent of their income."

"The Romneys thus limited their deduction of charitable contributions to conform to the Governor's statement in August, based upon the January estimate of income, that he paid at least 13 per cent in income taxes in each of the last 10 years," Malt added.