Chief executives of U.S. corporations earned 262 times the pay of the average worker in 2005, the second-highest level in the 40 years the data's been kept, an economic research group said this week.

Last year, the average CEO was paid $10.9 million a year, or 262 times an average worker's earnings of $41,861, the Economic Policy Institute said Wednesday.

The research group also found a CEO earned more in one workday in 2005 than an average worker earned in 52 weeks.

The group includes salary, bonuses, stock options and other payments in its definition of CEO pay.

Soaring levels of executive pay have outraged shareholders at some companies including Home Depot and Morgan Stanley, and securities regulators have proposed heightened disclosure of CEO compensation to empower investors to reign in undeserving corporate chiefs.

CEO pay relative to workers' pay has grown steadily since at least the 1960s, the institute says.

In 1965, CEOs of major U.S. companies earned 24 times more than the average worker. In 1978, corporate chiefs earned 35 times more than workers and in 1989, 71 times more.

The ratio hit 300 at the end of the recovery in 2000, the group said.

CEO pay slumped in 2002, with the ratio falling to 143, EPI said.

U.S. corporate officers' pay is typically higher than that in other countries. In 2003, for example, U.S. executives earned 1.6 times what their counterparts did in the United Kingdom. The same year, U.S. CEOs' incentive payments like options were 5.2 times what they were for U.K. CEOs, according to a University of Pennsylvania study.

The SEC is expected to release its final proposal to revamp executive pay disclosure by the end of the summer. SEC Chairman Christopher Cox has said the new rules will include requirements about options backdating.

Last week, the chairman of the Senate Finance Committee urged authorities to investigate allegations that several publicly traded companies backdated option grants to executives.

"If the tax laws are inadequate, I want to beef them up," Senate Finance Committee Chairman Charles Grassley, R-Iowa, said after a hearing on corporate-tax policy on June 13.