Mortgage rates surged again this past week, completing a consistently steep ascent in May, according to data released Thursday by Freddie Mac.

The 30-year fixed-rate average jumped to 3.81 percent with an average 0.8 point, its highest mark in the past year. May began with the 30-year hovering at 3.35 percent, well below last year’s reading at the start of the month; however, four straight weeks of increases have pushed the average above last year’s reading of 3.75 percent.

The 15-year fixed rate average followed suit, rising to 2.98 percent from 2.77 percent last week, with an average 0.7 point. One year ago, the average was 2.97 percent.

Hybrid adjustable rate mortgages, on the other hand, remained below their averages from last May. The five-year ARM rose slightly to 2.66 percent, down year-over-year from 2.84 percent, and the one-year dropped slightly to 2.54 percent, down from 2.75 percent a year ago.

A Freddie Mac executive pegged the rising fixed-rate averages to some recent signs of economic improvement, including higher home prices and improving consumer confidence.

Mortgage rates jump to highest mark in a year.