Despite an abundance of techies, New Englanders lag when it comes to filing their federal tax returns electronically. The Internal Revenue Service isn’t sure why.

In a conference call Thursday, Commissioner Mark Everson said he expects about half of the country’s 133 million tax returns to be filed electronically.

“E-filing has reached a critical mass, and it is becoming the rule rather than the exception,” Everson said.

But Vermont, Connecticut, Massachusetts and Rhode Island all ranked in the bottom eight, and New Hampshire – in the bottom 15, at 44 percent – wasn’t much better.

Peggy Riley, the IRS’ spokeswoman for New Hampshire, said she couldn’t explain her state’s low rate. She said the state does not fit the IRS profile for low participation – it doesn’t have a large and diverse population, there’s not much of a language barrier, and access to technology isn’t much of an issue.

New England generally is considered to be tech-savvy, with Boston-area universities and high-tech industries as the main draw.

Nationally, of 55 million returns filed as of March 4, 72 percent were e-filed – up from 67 percent the previous year. While that percentage is expected to decline as the April 15 deadline approaches, the IRS expects more than half of all individual returns to be filed electronically this year.

In Rhode Island, the IRS said, the rate of e-filing has gone up about 8 percent this year, compared to the same time last year.

The fastest-growing segment of e-filed returns is among people who do their own returns on a home computer. That number is 9.8 million this year, up more than 14 percent from the same period last year, IRS figures show.