mortgage rates rose this week as home sales continue to decline and prices moderate from the highs seen over the past couple of years housingfinance agency freddie mac said in the week ending thursday the average rate on a 30year fixedrate mortgage rose to 555 from 513 last week a year ago this week the average rate was 287 average 15year rates were 485 up from 455 a week ago freddie mac said a year ago the average 15year fixedrate mortgage rate was 217 the average rate on a fiveyear treasuryindexed hybrid adjustablerate mortgage or arm was 436 down from 439 last week a year ago the fiveyear arm averaged 242 the combination of higher mortgage rates and the slowdown in economic growth is weighing on the housing market said sam khater freddie macs chief economist home sales continue to decline prices are moderating and consumer confidence is low but amid waning demand there are still potential homebuyers on the sidelines waiting to jump back into the market write to will feuer at willfeuerwsjcom