WASHINGTON — The number of U.S. households on the verge of losing their homes soared by nearly 15 percent in the first half of the year as more people lost their jobs and were unable to pay their monthly mortgage bills.

The mushrooming foreclosure crisis affected more than 1.5 million homes in the first six months of the year, according to a report released today by foreclosure listing service RealtyTrac.

The data show that, despite the Obama administration's plan to encourage the lending industry to prevent foreclosures by handing out $50 billion in subsidies, the nation's housing woes continue to spread. Experts don't expect foreclosures to peak until the middle of next year.

Foreclosure filings rose more than 33 percent in June compared with the same month last year and were up nearly 5 percent from May, RealtyTrac said.

More than 336,000 households received at least one foreclosure-related notice in June, according to the foreclosure listing firm's report. That works out to one in every 380 U.S. homes.

It was the fourth-straight month in which more than 300,000 households received a foreclosure filing, which includes default notices and several other legal notices that homeowners receive before they finally lose their homes. Banks repossessed more than 79,000 homes in June, up from about 65,000 a month earlier.

On a state-by-state basis, Nevada had the nation's highest foreclosure rate in the first half of the year, with more than 6 percent of all households receiving a filing. Arizona was No. 2, followed by Florida, California and Utah. Rounding out the top 10 were Georgia, Michigan, Illinois, Idaho and Colorado.

The Obama administration in March launched a $50 billion plan to give the lending industry financial incentives to modify mortgages to lower payments, but it's off to a slow start.

As of early July, about 130,000 borrowers were enrolled in three-month trial modifications under the plan.