Passage: In 1966 he invented dynamic random-access memory (DRAM), for which a patent was issued in 1968. Dennard was also among the first to recognize the tremendous potential of downsizing MOSFETs. The scaling theory he and his colleagues formulated in 1974 postulated that MOSFETs continue to function as voltage-controlled switches while all key figures of merit such as layout density, operating speed, and energy efficiency improve – provided geometric dimensions, voltages, and doping concentrations are consistently scaled to maintain the same electric field.  This property underlies the achievement of Moore's Law and the evolution of microelectronics over the last few decades.

Question: What year did he invent dynamic random-access memory?
1966