The average interest rate on 30-year fixed-rate mortgages climbed to 8.26% for the week ending Jan. 21, up from 8.18% last week, Freddie Mac said. The last time rates were higher was Sept. 13, 1996, when they hit 8.28%. Fifteen-year mortgages, a popular option for refinancing, also were up this week, with an average rate of 7.86%, compared with 7.78% last week. But one-year adjustable-rate mortgages averaged 6.56% this week, down from 6.61% the previous week. The rates do not include add-on fees known as points. The central bank increased rates three times last year. Separately, the Mortgage Bankers Assn. of America said that mortgage loan applications for the week ended Jan. 14 increased 18.8% from the previous week and were down 39.9% compared with the same week last year.