What percent of inmates have access to computers in US prisons?

This used to be easier to answer--zero in state prisons and very limited and monitored access in the federal prisons, but with the advent of J-Pay email (see the link below) the numbers are climbing.

Aside from J-Pay, inmates may have limited use of computers for GED classes those without high school diplomas are required to attend. These computers are networked in a closed system, and there is no outside (internet) connection. J-Pay has made it possible for inmates to send and receive internet emails from family and friends, both much cheaper and faster than snail-mail has been able to provide. Additionally, security is enhanced and facilitated by automated monitoring not possible with conventional mail delivery.