Mortgage rates, which took some dramatic dips in 2012, were among the lowest on record this year, according to data released by Freddie Mac on Thursday.

The 30-year fixed-rate average dropped to 3.35 percent, down 0.7 from the week before. It is substantially lower than the 3.95 percent level it reached during the final week of 2011.

The 15-year fixed-rate average, however, remained at 2.65 percent. That is down from last year when it was 3.24 percent.

Hybrid adjustable rates were mixed this week.

The five-year ARM decreased to 2.70 percent with an average 0.7 point, down from 2.71 percent last week. The one-year ARM rose to 2.56 percent with an average 0.5 point from 2.52 percent last week.

“Mortgage rates ended this year near record lows,” Frank Nothaft, Freddie Mac’s vice president and chief economist, said in a statement.

“The 30-year fixed-rate mortgage averaged 3.66 percent for 2012, the lowest annual average in at least 65 years,” he added. “Rates on 30-year fixed mortgages were nearly 0.6 percentage points below that of the beginning of the year, which translates into an interest payment savings of nearly $98,600 over the life of a $200,000 loan. Moreover, opting for a 15-year fixed mortgage at today’s rates, a homeowner could save an additional $138,400 in interest payments.”

During the week ending Nov. 21, the 30-year and 15-year fixed rates hit historic lows — 3.31 percent and 2.63 percent, respectively, according to Freddie Mac.