Badbob didn't really answer the question. As Jenstar says, the Internet and WWW are not interchangeable terms and the figures that Babbob gives are for the hosts, not the number of users with access. My guess would be about 20 users per host, so my take on it would between 500,000 and a million users, but that would be a wild stab. Access would have been limited to academic and military institutions and research establishments, primarily in the US, so there would be a limited number.