A report Thursday showed that prices of single-family houses have declined in the last month and year in Iowa, but two local markets are showing improvement, the National Association of Home Builders (NAHB) said. Iowa City and Waterloo experienced an increase in building permits, sales prices and employment, the association said in its monthly First American Improving Markets index. Twenty-three cities made the list for August, nearly doubling the number of cities on July’s list, the NAHB said in a news release. This is the first time any Iowa cities have made the list, which was led by cities in Texas that had shown improvements in the three categories monitored by the NAHB. The index is based on data from the U.S. Census Bureau, the U.S. Department of Labor and Freddie Mac. Earlier today, CoreLogic Inc. said that prices of single-family homes showed an overall decline in Iowa and the country.