A draft analysis of wage trends by the Oregon Employment Department has found a growing gap between the state's wealthy and the middle class and poor.

PORTLAND — A draft analysis of wage trends by the Oregon Employment Department has found a growing gap between the state's wealthy and the middle class and poor.

The study finds that the state's wealthiest are not only earning more, but the rate at which their incomes are growing far outpaces people earning less. Middle class earners continued to have stagnant wages for much of the past decade, with their pay falling back to 2001 levels in 2008, the latest year that figures are available.

Inflation-adjusted annual wages for Oregon's top 2 percent of earners hit $153,480 on average in 2008, up 29.5 percent from 1990.

Workers at the 50 percentile, meanwhile, earned $32,659 in 2008, an increase of just 2.4 percent over 1990 after adjusting for inflation.

"Wage inequality in Oregon rose steadily between 1990 and 2000, declined slightly in 2001 and 2002, and continued to increase to its peak in 2007," the study said.

The analysis considers only wages and not other sources of income such as earnings from investments.

"There's something going on at the very top, an explosion of the 'uber-rich,'" Bryce Ward, a senior economist with Portland-based consulting firm ECONorthwest, told The Oregonian. "There's been no growth in a decade for the middle."

Ward said he's concerned that its getting tougher for Americans to rise above their socio-economic origins.

"My concern is just with opportunity," Ward said. "There should be no correlation between your parents' earnings and yours," he said.

The Employment Department study compares wages for four different income groups of employees who worked all four quarters of a year between 1990 and 2008.

It found that those earning at the 50th percentile had inflation-adjusted wages grow 4.5 percent, from $31,866 in 1990 to a peak of $33,318 in 2004.

The group's income has fallen every year since then, finishing 2008 at $32,659, the lowest level since 2001.

In contrast, those at the top 98th percentile of earners saw their inflation-adjusted wages climb 31 percent in the same 18 years, from $118,453 in 1990 to a peak of $155,496 in 2007.

The economic downturn has affected high earners. Their income dipped to $153,480 in 2008.