Fixed-rate mortgages held steady from the prior week’s record lows, helping to drive homebuyer affordability across the nation.

The Freddie Mac survey showed the 30-year FRM averaged 3.78% for the week ending Thursday — a new low — ticking down from the prior week’s record average of 3.79%. Last year at this time, the 30-year FRM averaged 4.60%.

The 15-year FRM, a popular refinancing choice, averaged 3.04%, unchanged from last week‘s record average. A year ago, the average rate for a 15-year FRM was 3.80%.

Five-year, Treasury-indexed hybrid adjustable-rate mortgages averaged 2.83%, again unchanged from last week and down from 3.41% a year earlier.

And one-year, Treasury-indexed ARMs averaged 2.75%, down from last week’s average of 2.78% and down from 3.11% last year.

“Mortgage rates were virtually unchanged this week with fixed-rate loans remaining at record lows and helping to drive homebuyer affordability,” noted Freddie Mac chief economist Frank Nothaft.

The National Association of Realtor’s housing affordability index reached an all-time record high in the first quarter. And in April, existing home sales rose to the highest rate since January with an annualized rate of 4.62 million homes purchases increasing in all regions.

Similarly, sales of new homes also rose last month, beating the market consensus forecast, said Nothaft, adding that the Federal Housing Finance Agency‘s purchase-only house price index rose 0.5% in the first quarter from a year earlier, representing the first four-quarter increase since the first quarter of 2007.

Home loan analytics firm Bankrate, which surveys large banks, reported the 30-year FRM did not change from last week’s rate of 3.97%, while the 15-year FRM ticked down to 3.19% from 3.2%. The 5/1 ARM rose to 3.02% from 3.0%.