More than three-quarters of US homes now enjoy broadband service, even though the nation's Internet penetration rate has leveled off, according to a new study.

In its latest telephone survey of American consumers, Leichtman Research Group Inc. (LRG) found that 78 percent of US households now have broadband service, the highest total yet. That's up from close to 70 percent four years ago.

More impressively, nearly all US homes with Internet service now subscribe to some kind of broadband provider, LRG revealed. Some 94 percent of Internet households have broadband connections, up from 92 percent last year, 75 percent in 2008, and just 33 percent in 2004.

Yet the overall home Internet penetration is no longer rising in the US. The latest research showed that 83 percent of US homes now have Internet service, about even with last year's take rate.

In another notable finding, the study found that the number of consumers using smartphones to access the Web at home is rising sharply. Some 55 percent of adults now log onto the Web at home with their phones, up from 44 percent a year ago. Moreover, 64 percent of broadband subscribers log onto the Web at home with their smartphones, up from 52 percent in 2012.

Smartphone use also surged among consumers without Internet access at home. Nearly one-fifth of respondents, or 19 percent, without online connections at home now use smartphones to get on the Web, up from 12 percent a year earlier.

"While overall online penetration at home has flattened, broadband has grown by attracting previous narrowband customers, late adopters of online at home, and movers into new households," said LRG President and Principal Analyst Bruce Leichtman in a prepared statement. "Despite an increasingly limited base of potential new subscribers, and some consumers opting to solely access the Internet on a smartphone, broadband will continue to grow at a modest pace for the next few years."

Interestingly, the LRG survey did not find that much evidence that more broadband subscribers are cutting the video subscription cord to watch TV programming online. Some 9 percent of households report that they have broadband service but don't subscribe to a multi-channel video service, up only slightly from 8 percent each of the past two years.

— Alan Breznick, Cable/Video Practice Leader, Light Reading