Mortgage rates crept lower again this week, with the average 30-year fixed-rate mortgage falling three basis points to 6.81%, according to Freddie Mac’s weekly rate survey.

The 15-year rate also declined this week, ticking down one basis point to 5.96%.

It marked the third week in a row that interest rates have edged downward after rising slightly during the week ending May 29.

“Mortgage rates moved lower, with the average 30-year fixed rate reaching a four-week low,” Sam Khater, Freddie Mac’s chief economist, said in a statement. “More available inventory to choose from, coupled with this week’s decline in mortgage rates, could be the spark to get potential homebuyers off the sidelines.”

Both the 30-year and 15-year rates remain above their respective 52-week averages of 6.69% and 5.88%, according to Freddie Mac data.