The Commodore 64 wasn't released until August 1982 and the PC did take a while to beat it in marketshare. The VIC-20 was Commodore's monster seller before that (1st computer to hit 1 million unit sales). I did not see the VIC-20 listed on the chart, so I suspect it is in the other category. Given that is was released in 1980, I find it likely that it outsold Apple and the chart is hiding the actual Commodore number. Never mind the lack of Timex / Sinclair or TI computers in that spreadsheet. Calling Apple #1 when its market share never exceeded 16% is a bit off.