In 2009, the average U.S. Internet user spent 13 hours per week online. This number is down slightly from last year. Thanks to the large interest in the presidential election and the financial crisis, the average Internet user was online for roughly 14 hours per week in 2008. According to a new poll from Harris Interactive, users between the ages of 30 to 39 are the most active Internet users. On average, this group is online for 18 hours per week.

Overall, the average time online for U.S. Internet users has gone up from seven hours in 1999 to close to nine hours in 2003 and up to 11 hours in 2007. We should note that these numbers only include adults. According to Nielsen, which looked at all U.S. Internet users, the average usage per week is closer to 17 hours.

98% of All Computer Users in the U.S. are Online

The number of adults who are online has not changed since 2007. In total, 184 million adults regularly surf the Internet at work, home or school. While the number of adults who are online has not changed, the number of adults who access the Internet at home has increased from 66% in 2005 to 76% in 2009. Ten years ago, only 56% of all adults accessed the Internet from home. In total, 98% of all computer users are now online.

While users between 30 and 39 are the most active Internet users, those between 25 and 29 are the most likely to spend more than 24 hours per week online. 25% of 25- to 29-year-olds surf the Net between 24 and 162 hours per week - sadly, Harris Interactive doesn't tell us how many of these users actually spend every minute of the week online.

Online Shopping

With regards to online shopping, Harris found that 50% of adults bought something online in the last month. Not surprisingly, 30- to 39-year-olds are the most active online shoppers.

How High Will These Numbers Go?

Given how popular online video and social networks have become over the last few years, chances are that the average number of hours spend online will continue to grow slowly over the next few years. U.S. Internet users who watch TV online watch close to 18 hours of online video per week already. In the U.K., the average Facebook user spends close to three full days per year on the site. Without doubt, however, there will be a natural limit to how much time per week people will spend online.