The percentage of Americans with high-speed internet connections at home has reached 70 per cent, while just three per cent still use dial-up.
The Pew Research Center's Internet & American Life Project report says the percentage of high-speed users represents a small but statistically significant rise from the 66 per cent of adults who said they had home broadband in April last year.
The percentage using dial-up as of May 2013 has held steady at three per cent for the past two years, Pew has found, but is down sharply from a peak of 41 per cent in 2001.
Overall, 85 per cent of Americans use the internet, the report said.
Of those who lack a high-speed connection at home, 10 per cent have smartphones that can access the web.
As previous research has found, those with the highest rates of home broadband use continue to be college graduates, adults under 50 and adults living in households earning at least $US50,000 ($A55,650) a year.
Whites and adults living in urban or suburban areas also have above-average rates.
"We've consistently found that age, education and household income are among the strongest factors associated with home broadband adoption," said Kathryn Zickuhr, research associate for Pew and lead author of the report, on Monday.
"Many dial-up users cite cost and access as the main reasons they don't have broadband but for adults who don't use the internet at all, a lack of interest is often the main issue."
The survey notes that more than half of all American adults own a smartphone but it did not determine whether this constitutes "broadband" speed.
