Nielsen//NetRatings said broadband penetration reached 51% in July, a sharp increase from last July's 38%.
The company said 63 million Web users connected to the Internet via broadband, versus 61.3 million using narrowband.
Not surprisingly, broadband penetration was greatest among younger demographics, with 18-20 leading the way at 59%. The 25- to 34-year-old age group boasted penetration of 55%.
But numbers were still strong at the older groups, with 49% of 50- to 54-year-olds saying they had broadband and 46% of those 55-64.