Figure from ROBOT, Moravec, Oxford, 1998, Chapter 3: Power and Presence, page 68
AI computers, rising from .1 to 1 MIPS in 1960, then from 1 MIPS to 1000 in 1990s

The big freeze
From 1960 to 1990 the cost of computers used in AI research declined while their numbers increased as funding decreased. The dilution absorbed computer-efficiency gains during the period, and the power available to individual AI programs remained almost unchanged at 1 MIPS--less than insect power. AI computer cost bottomed in 1990, and since then power has doubled yearly, to several hundred MIPS by 1998. The major visible exception to this pattern is computer chess, shown by a progression of knights, whose prestige lured the resources of major computer companies and the talents of programmers and machine designers. Exceptions also exist in less public competitions, like petroleum exploration and intelligence gathering, whose high return on investment warrants access to the largest computers.