Mortgage rate hikes have cut housing availability.

The National Assn. of Realtors said the housing availability index was 109.4 for May, down from 111.9 in April. The May index means that a family earning the national median income of $29,742 a year would have had 109.4% of the income needed to qualify for a conventional loan covering 80% of the median house price of $85,400 that month. In April, a family earning the median income would have had 111.9% of the income needed to qualify for an 80% mortgage on a median-priced home. The median is the point at which half the houses sell for more and half for less.