I say 1985, because that was when the Amiga 1000 and Atari ST were released, and two of the leading microcomputer manufacturers largely abandoned the 8-bit architectures in favor of 16-bit architectures. The Tandy 1000 and Macintosh, both 16-bit computers, were released a year earlier. If you go by the end of production of 8-bit PCs, then the 8-bit era probably went into the early 90s.