The increase in August from the month before was about in line with the average over the past two decades. The supply of homes has risen at a more normal pace in recent months after surging in late 2005 and 2006 as home sales plunged. Prices are still falling in much of the country, particularly in Florida and parts of California, Arizona and Nevada where prices rose the fastest during the boom of the first half of this decade. Mortgage lenders have severely tightened their credit standards recently, making it harder for many people to obtain loans and adding to downward pressure on home prices. Inside Mortgage Finance, a trade publication, said originations of home-mortgage loans in August fell more than 30% from a year earlier, according to a survey of brokers. A rise in foreclosures is also increasing the supply of homes for sale in many areas.