Sales of foreclosures and other distressed properties continue to weigh down overall Chicago-area home prices, which declined 2.9 percent in September compared to the same time last year.

That’s according to the real estate information company CoreLogic, which released its monthly Home Price Index on Tuesday. Unlike other monthly home price data, CoreLogic tracks distressed properties as well as regular home sales. (Distressed properties include short sales and foreclosures, or real estate owned transactions.)

“The foreclosures are having a pretty substantial impact on the market because there’s still so many of  them,” said the Illinois Association of Relators’ Jon Broadbooks, who added that foreclosures can take as long as 22 months to wind their way through the legal system. “Until earlier this year, many of them were bottlenecked in the court system. Now they’re beginning to move through, and so that’s having somewhat of a dampening effect on prices.”

Without foreclosures or short sales, home prices in Chicago increased nearly two percent compared to September last year.

Nationally, home prices increased five percent, including distressed sales. CoreLogic said it was the biggest increase in more than six years — since July 2006 — and the seventh consecutive monthly year-over-year price increased. All but seven states are experiencing these year-over-year price increases.

Illinois is second only to Rhode Island as having the greatest home price depreciation.