The average interest rate for a 30-year mortgage jumped 21 basis points last week, from 6.62% to 6.83%, according to Freddie Mac, which does a weekly survey of rates in the industry.

Rates remained below 7% for the 13th consecutive week, an important threshold, said Sam Khater, Freddie Mac’s chief economist, in a statement. He noted that rates were also below the same week a year ago.

“At this time last year, rates reached 7.1% while purchase application demand was 13% lower than it is today, a clear sign that this year’s spring homebuying season is off to a stronger start,” Khater said.

The increase in rates had an immediate impact on the mortgage market, however. The Mortgage Bankers Association (MBA) said that total applications declined by 8.5% for the week ending April 11.

Refinances fell 12% and many borrowers opted for adjustable-rate mortgages, which feature a low initial rate.

Freddie Mac’s survey released on Thursday found that the 15-year fixed-rate mortgage averaged 6.03% last week, also up 21 basis points from the previous week. A year ago, the 15-year mortgage averaged 6.39%.