In its latest report, RealtyTrac announced that foreclosure activity fell in 84 percent of metro areas with at least 200,000 residents on a year-over-year basis.

That’s the good news. The real question is how long will it last?

According to the company’s mid-year report, California, Nevada and Arizona cities accounted for all top 10 metro foreclosure rates and 15 of the top 20 metro foreclosure rates in the first half of the year. Only one Florida metro area posted a foreclosure rate among the top 20 (Cape Coral-Fort Myers at No. 12) in sharp contrast to the first half of 2010, when Florida cities accounted for nine of the top 20 metro foreclosure rates nationwide.

Also posting foreclosure rates ranking among the top 20 were Boise City-Nampa, Idaho, Atlanta-Sandy Springs-Marietta, Ga., Greeley, Colo., and Salt Lake City, Utah.

“Foreclosure activity continued to slow in the first half of 2011, especially in the most foreclosure-saturated markets and in markets where the judicial foreclosure process is used,” said James J. Saccacio, chief executive officer of RealtyTrac. “The 20 metro areas with the biggest year-over-year decreases in foreclosure activity were all in states with judicial foreclosure processes — New York, Maryland, Florida, New Jersey, Connecticut, Massachusetts, and Illinois.”

“These dramatic decreases indicate the foreclosure pipeline continues to be clogged in many local markets across the country, sometimes by a glut of already-foreclosed properties that are not selling quickly, sometimes by a mountain of improperly filed foreclosures that are blocking the inflow of new foreclosure filings — and sometimes by both,” he added.

Nevada, Arizona and Southern California still contain some of the most foreclosure-damaged cities in the country. The greater Las Vegas metropolitan area continued to post the nation’s highest metro foreclosure rate, with one in every 19 housing units (5.36 percent) receiving a foreclosure filing during the first half of 2011—nearly six times the national average. A total of 43,944 Las Vegas properties received a foreclosure filing during the six-month period, according to the report, a decrease of 18 percent from the previous six months and also an 18 percent decrease from the first half of 2010.

The greater Reno, Nevada metropolitan area also ranked among the top 10 in the first half of 2011. One in every 34 housing units (2.96 percent) in the Reno-Sparks area received a foreclosure filing during the six-month period, the nation’s seventh highest metro foreclosure rate.

Despite a decrease in foreclosure activity from both the previous six months and the first half of 2010, the Phoenix-Mesa-Scottsdale, Ariz., metro area posted the nation’s second highest metro foreclosure rate during the first half of 2011. A total of 60,985 Phoenix properties received a foreclosure filing during the six-month period, a decrease of 8 percent from the previous six months and a decrease of nearly 17 percent from the first six months of 2010.

Seven California metro areas also fell into the top 10, including Modesto at No. 3 with one in every 30 housing units (3.32 percent) receiving a foreclosure filing, Stockton at No. 4 (3.24 percent), Riverside-San Bernardino-Ontario at No. 5 (3.21 percent), Vallejo-Fairfield at No. 6 (3.09 percent), Bakersfield at No. 8 (2.78 percent), Merced at No. 9 (2.78 percent), and Sacramento-Arden-Arcade-Roseville at No. 10 (2.53 percent).

While it didn’t come close to the top of the list, Seattle saw a 10 percent increase in foreclosure activity during the first six months of the year, the biggest jump of the twenty biggest metro areas. Houston and Minneapolis also saw their foreclosure activity surge.

Housing economists agree that today’s foreclosures are, for the most part, the result of the stagnant economy and stalled job creation. The sub-prime and exotic mortgage issues have been, for the most part, flushed from the system. These foreclosures are the result of homeowners losing their jobs, or finding replacement jobs that bring in less income.

And without income, it’s hard to make your mortgage payment.