 In 1998, all of the United States' backbone networks had utilized the slowest data rate of 45 Mbit/s.However, technological improvements allowed for 41 percent of backbones to have data rates of 2,488 Mbit/s or faster by the mid 2000s.The first packet-switched computer networks, the NPL network and the ARPANET were interconnected in 1973 via University College London.