Mortgage rates declined this past week, with adjustable-rate mortgages hitting new lows, according to Freddie Mac’s latest Primary Mortgage Market Survey. Adjustable-rate mortgages hit new lows, with the 5-year Treasury indexed ARM averaging 2.91% this past week, down from 2.97% a week earlier. Last year, the same rate hit 3.45%. The 1-year, Treasury-indexed ARM hovered at 2.79%, down from 2.98% a week earlier and 3.23% last year. The 30-year, fixed-rate mortgage remained below 4%, averaging 3.98% last week, down from 4% a week earlier.  A year ago, the same rate hovered at 4.4%. The 15-year, FRM averaged 3.3%, down from 3.31% last week and 3.77% a year earlier. “Mortgage rates eased slightly this week with fixed-rate loans hovering above all-time lows and ARMs reaching a new nadir,” said Frank Nothaft, vice president and chief economist of Freddie Mac. “The high-degree of homebuyer affordability in recent months translated into a 1.4% pickup in existing home sales during October, according to the National Association of Realtors. NAR also reported that contract cancellations were up in October as well, which restrained sales from achieving a stronger rebound.” Write to Kerri Panchuk.