As of April 2012, 53% of American adults age 65 and older use the internet or email.

Pew reports:

As of April 2012, 53% of American adults age 65 and older use the internet or email. Though these adults are still less likely than all other age groups to use the internet, the latest data represent the first time that half of seniors are going online. After several years of very little growth among this group, these gains are significant.