80% of Americans use the internet, and spend an average of 13 hours a week online

"The Harris Interactive poll, released Wednesday, found that 80 percent of U.S. adults go online, whether at home, work, or elsewhere. Those who surf the Net spend an average of 13 hours per week online, but that figure varies widely. Twenty percent are online for two hours or less a week, while 14 percent are there for 24 hours or more.
The average number of hours that people spend online each week has grown over the years, hovering at 7 hours from 1999 through 2002, 8 or 9 hours from 2003 through 2006, and 11 hours in 2007. The level hit its peak at 14 hours in October 2008--after the global recession had set in and just before the U.S. presidential election.
The jump in time spent in cyberspace likely stems from a few factors, according to Harris. More people are comfortable using the Internet. More of them are shopping and watching TV online. In addition, the number of Web sites and online applications has increased. Harris adds that the recession may also play a role since surfing the Net at home is free (after paying monthly access fees), while going out means spending money.
The age group that spent the most time online per week: 30- to 39-year-olds, at 18 hours.
The total number of U.S. adults on the Internet is 184 million, around 80 percent of the total population, according to the poll. That figure is virtually the same as in 2008 but is a big jump from 1999, when it reached at 56 percent, and from 1995, when the figure was a mere 9 percent."
Source: Harris Interactive poll of 2,029 people, conducted between mid July and mid October, reported by CNET, 23rd December 2009