Pending home sales, a leading indicator in the housing market, showed a decline in August, just one month after reaching a two-year peak.

The National Association of Realtors reported Thursday that the Pending Homes Sales Index, which is based on contract signings rather than actual sales, was down 2.6 percent nationally to 99.2 last month.

In July, the index rose to its highest level in more than two years, 101.9. Despite the decline, it was 10.7 percent higher than August 2011 when it was 89.6.

NAR chief economist Lawrence Yun said it is not unusual to see some fluctuation in the monthly data.

“The performance in month-to-month contract signings has been uneven with ongoing shortages of lower priced inventory in much of the country, and across most price ranges in the West, but activity has remained at notably higher levels this year,” Yun said in a statement. 

“The index shows 16 consecutive months of year-over-year increases, and that has translated into a higher number of closed sales. Year-to-date existing-home sales are 9 percent above the same period last year, but sales were relatively flat from 2008 through 2011.”

According data from RBIntel, pending sales in the Washington metro area were mixed in August. Fairfax County saw the biggest decline in pending sales, falling 10.31 percent from July. In contrast, Prince George’s County saw the biggest increase in pending sales, rising 8.65 percent. This came after pending sales in the county fell 11.37 percent from June to July.

The District decreased 3.02 percent, while Montgomery County declined 2.34 percent.

Arlington and Alexandria City were up 4.55 percent and 2.66 percent, respectively.