Pending sales of homes in the United States dropped slightly in August, according to the National Association of Realtors. However, the organization said the level of activity remains healthy and that pending sales have experienced year-over-year growth for the past year.

The Pending Home Sales Index dropped to 109.4 in August, a 1.4 percent decrease from the figure of 110.9 in July. The activity in August was 6.1 percent higher than August of 2014, when the Pending Home Sales Index stood at 103.1, making it the 12th consecutive month with a figure higher than the same month in the previous year.

The National Association of Realtors defines a pending sale as one where a contract has been signed but the transaction has not been finalized. In most cases, the sale is closed within one or two months of the signing.

The Pending Home Sales Index uses a national sample large enough to represent about 20 percent of existing home sales. A figure of 100 means the sales activity is equal to the average activity during the year of 2001, when the Pending Home Sales Index was first measured. The volume of existing home sales in that year was between 5 million and 5.5 million, which the National Association of Realtors says is normal for the current population in the United States.

Lawrence Yun, chief economist for the National Association of Realtors, says that demand for homes is still higher than the available supply even with the slight decline in pending sales, leading to higher home prices in several markets. Yun says he expects pending sales to remain steady for the rest of the year, though changes to the mortgage closing process could lead to delays in some sales.

"Pending sales have leveled off since mid–summer, with buyers being bounded by rising prices and few available and affordable properties within their budget," said Yun. "Even with existing–housing supply barely budging all summer and no relief coming from new construction, contract activity is still higher than earlier this year and a year ago."

The West was the only region where the Pending Home Sales Index increased, going up 1.8 percent to 104.9. This figure was also 7.6 percent higher than August of 2014.

The Northeast had the largest decrease in its Pending Home Sales Index, falling 5.6 percent to 93.3. However, this activity still put it 8.9 percent above the previous year.

Pending sales in the South dropped 2.2 percent to an index of 121.5, a 4.1 percent increase from August of 2014. The index in the Midwest fell by only 0.4 percent to 107.4, a 6.5 percent increase from the previous year.

The National Association of Realtors expects that the national median price for an existing home will increase 5.8 percent this year to $220,300. Yun says there is also an expectation that existing home sales in 2015 will increase 7 percent to about 5.28 million. However, this pace would still be 25 percent below the peak set in 2005, when 7.08 existing home sales were recorded.

The report on the Pending Home Sales Index was issued shortly after the National Association of Realtors released its monthly update on existing home sales. The organization says the annual pace dropped 4.8 percent to 5.31 million in August, but that this pace was 6.2 percent higher than the previous year. The median price for an existing home in this month was $228,700, a 4.7 percent year-over-year increase.