The Mortgage Bankers Association (MBA) today released its Weekly Mortgage Applications Survey for the week ending October 6.  The Market Composite Index, a measure of mortgage loan application volume, was 599.1, a decrease of 5.5 percent on a seasonally adjusted basis from 633.9 one week earlier.  On an unadjusted basis, the Index decreased 5.3 percent compared with the previous week and was down 13.3 percent compared with the same week one year earlier.The seasonally-adjusted Refinance Index decreased by 5.8 percent to 1857 from 1970.8 the previous week and the Purchase Index decreased by 5.3 percent to 383.3 from 404.6 one week earlier. Other seasonally adjusted index activity includes the Conventional Index, which decreased by 5.5 percent to 888 from 939.3 the previous week, and the Government Index, which decreased 5.8 percent to 117.5 from 124.8 the previous week.