85% of American adults use the internet as of May 2013, representing a new high point for internet adoption, according to [pdf] a new report from the Pew Research Center’s Internet & American Life Project. That still leaves 15% of adults who do not use the internet or email, for a range of reasons. The study takes a look at the demographics of this group, with some fairly predictable – but nevertheless interesting – results.

One of the biggest discrepancies in internet adoption is found when sorting by educational attainment. Respondents with no high school diploma were 10 times more likely than college graduates to be offline (41% vs. 4%), with a high proportion (22%) of high school graduates without any college education also offline.

Age, predictably, also factors in heavily. While just 2% of 18-29-year-olds are offline, that figure rises to 8% among 30-49-year-olds and 17% among 50-64-year-olds, before jumping to 44% of the 65+ group (including 62% of adults aged 77 and up).

Interestingly, although Hispanic cell phone users are more prone to using their device to go online than the average American, Hispanic adults are more likely than the average adult to be offline (24% vs. 15%).

Household income (HHI) also plays a role: 24% of respondents with HHI of less than $30,000 are offline, compared to 4% with HHI of more than $75,000. Rural Americans are also more likely to be offline.

It’s not surprising to see lower-income and rural Americans more likely to be offline. Separate results from the study indicate that 19% of offline adults say they don’t use the internet because of the cost, while 7% cite lack of availability or access. The main reasons for not going online, though, concern relevance (34%) and usability (32%).

Other Findings:

Usability has spiked as a reason for not going online, with this year’s 32% up from 18% in 2010. Availability is a much smaller issue than it was in 2007 and 2009.

14% of offline adults said they used to use the internet, while 44% have asked a friend or family member to go online for them at some point.

Fewer than 1 in 10 offline adults would like to start using the internet or email.

9% of American adults use the internet, but not from home. Incidence of out-of-home use is higher among lower-income respondents and those with low levels of educational attainment.

Among those who use the internet outside the home, the main reasons for not using the internet at home are price (42%) and relevance (17%).

About the Data: The findings in the report are based on data from telephone interviews conducted by Princeton Survey Research Associates International from April 17 to May 19, 2013, among a sample of 2,252 adults ages 18 and older. Telephone interviews were conducted in English and Spanish by landline and cell phone. For results based on the total sample, one can say with 95% confidence that the error attributable to sampling is plus or minus 2.3 percentage points.