"Following its 1980 release, Zork I became a bestseller from 1983 through 1985. By 1986, the game had sold 380,000 copies, with 680,000 sales for the trilogy ov

"Following its 1980 release, Zork I became a bestseller from 1983 through 1985. By 1986, the game had sold 380,000 copies, with 680,000 sales for the trilogy overall, comprising one-third of Infocom's two million game sales" https://en.wikipedia.org/wiki/Infocom https://en.wikipedia.org/wiki/Infocom