Housing prices peaked in early 2005 began declining in 2006 (see also United States housing market correction). Year-to-year decreases in both U.S. home sales and home prices accelerates rather than slowing with U.S. Treasury secretary Paulson calling "the housing decline ... the most significant risk to our economy." Home sales continue to fall. The decrease in existing-home sales is the steepest since 1989. In Q1/2007 S&P/Case-Shiller house price index records first year-over-year decline in nationwide house prices since 1991. The subprime mortgage industry collapses foreclosure activity increases and rising interest rates threaten to depress prices further as problems in the subprime markets spread to the near-prime and prime mortgage markets.