WASHINGTON (AP) — Long-term U.S. mortgage rates this week jumped to their highest level since the start of August, raising costs for would-be homebuyers.

Mortgage buyer Freddie Mac said Thursday that the average rate on 30-year, fixed-rate mortgages climbed to 4.60 percent from 4.54 percent last week. The average rate has surged from 3.78 percent a year ago, posting the largest annual gain since May 2014.

The average rate on 15-year, fixed-rate loans rose to 4.06 percent this week from 3.99 percent last week.

Solid job growth has boosted demand from would-be homebuyers. But rising prices, a shortage of sales listings and higher rates have been a drag on sales. The National Association of Realtors said last month that existing homes have tumbled 1.5 percent over the past year.