Finding data on accessing and use of the internet is very difficult. However tables recently released from the US Census Bureau's Current Population Survey (CPS) School Enrollment and Internet
Use Supplement do provide some insights.
The tables display national and state level data and
examine householder and individual characteristics by school enrollment,
age, race, sex and Hispanic origin. Additional tables use data from the
Survey of Income and Program Participation (SIPP) to examine how and
why people connect to the Internet. The CPS has been collecting data on
computers and Internet use periodically since 1984. SIPP data on this
subject have been collected since 1998.
These data tables appear on the US Census Computer and Internet Use page.