WASHINGTON (Reuters) - U.S. mortgage rates dropped to the lowest level in nearly two months this week, a trend that if sustained could boost home sales in the coming months.

The average rate on the popular 30-year fixed-rate mortgage fell to 6.60%, the lowest level since the week ending Oct. 24, from 6.69% last week, mortgage finance agency Freddie Mac said on Thursday. It has now declined for three straight weeks. The rate averaged 6.95% during the same period a year ago.

"The combination of mortgage rate declines, firm consumer income growth and a bullish stock market have increased homebuyer demand in recent weeks," said Sam Khater, Freddie Mac chief economist. "While the outlook for the housing market is improving, the improvement is limited given that homebuyers continue to face stiff affordability headwinds."