WASHINGTON, Sept. 21 (Xinhua) -- U.S. mortgage applications last week rose slightly, according to the latest Weekly Mortgage Applications Survey released Wednesday by the U.S. Mortgage Bankers Association (MBA).

The MBA said the Market Composite Index of U.S. mortgage applications, a measure of mortgage loan application volume, rose 0.6 percent in the week ending Sept. 16 on a seasonally adjusted basis from the previous week.

The Refinance Index rose 2.2 percent from the previous week, while the seasonally adjusted Purchase Index fell 4.7 percent.

Meanwhile, the four-week moving average for the seasonally adjusted Market Index was down 3.15 percent. The four-week moving average fell 3.91 percent for the seasonally adjusted Refinance Index and decreased 0.54 percent for the Purchase Index, according to the survey.

In addition, the association said the average contract interest rate for 30-year fixed-rate mortgages last week decreased to 4.07 percent from 4.08 percent, and the average contract interest rate for 15-year fixed-rate mortgages fell to 3.46 percent from 3.52 percent.

The latest data are based on an enhanced sample which captures more than 75 percent of all retail and consumer direct channel mortgage applications, compared to 50 percent previously. The survey has been conducted weekly since 1990, collecting responses from mortgage bankers, commercial banks and thrifts.