NEW YORK (CNN/Money) - Mortgage rates were mixed last week, with longer-term rates pulling back slightly, mortgage financier Freddie Mac said Thursday in its latest report.

"Stronger growth in the economy will invariably translate into higher mortgage rates in the future, particularly for ARM products," said Frank Nothaft, Freddie Mac vice president and chief economist.

"However, the rise in mortgage rates will be measured, not extreme, and that will help keep the housing industry stable and affordable in the coming months."

The rate on 30-year fixed-rate mortgages averaged 5.98 percent in the week ending July 22, with an average 0.6 point payable up front, down modestly from 6 percent the previous week, Freddie Mac said.

A year earlier, the rate on the 30-year fixed-rate loan averaged 5.67 percent.

The 15-year mortgage rate eased to 5.39 percent from 5.40 percent, also with 0.6 point payable up front. Last year, rates stood at 5 percent.

One-year adjustable rate mortgages (ARMs) averaged 4.12 percent, up from 4.02 percent the week prior, with 0.6 of a point payable up front. At this time last year, the average rate for ARMs was 3.58 percent.

Freddie Mac's (FRE: down $0.76 to $64.38, Research, Estimates) average mortgage rates are based on a survey of 125 lenders nationwide.