This Nielsen//NetRatings press release says that “nearly three-quarters of U.S. active Web users connected at home via broadband in May, growing 15 percentage points over a year ago, when just 57 percent of active Web
users relied on broadband connections at home”.Further,”the total number of home broadband users has grown 30 percent year over year, from 78.6 million in May 2005 to 102.5 million in May 2006, while the number of narrowband users has dropped 31 percent in the same time period, from 58.8 million to 40.3 million”.

U.S. Broadband Composition Reaches 72 Percent at home