In the UK there were about 2.5m Amstrad's (of various models) sold, similar for Spectrum, Comomodore 64 less. Amiga's and Atari's weren't for sale until the tail end of the 80s (and even then, Amiga had sold just ~ 400K between 1988-1990). All together around looks like in in 5 households had a computer, and the distribution favored higher income ones - in working class areas much fewer would. Before 1987 even less.
I started doing the maths after reading your first two sentences, but you had already done it.
I make ‘80s computers in Ireland a bit rarer than you at about 1 in 9 households, however that means many kids at school would have a couple in their class with a computer, with the number growing as they progressed through school.
I’d spin the same data differently: not that uncommon and growing quickly.
Depends what you're comparing it against though :)
Today (including smart phones) you're talking about multiple computers per household, probably more computers in the house than there are people. So one per "40ish people" was (compared to now) "rare".
So, in my original post when I said "rare" - I meant "a few per class". In my 80's childhood there were maybe 2 or 3 people in the class who had a computer (of any kind) at home. The school had 2 computers (BBC Micro) for student access (for over 600 students.) Most were completely uninterested.
Bear in mind that the numbers in the UK and surrounds were likely higher than that because the UK was an epicentre of home-computer development. Sinclair, Acorn etc were all at their height so penetration in that market was likely a bit higher.
In the UK there were about 2.5m Amstrad's (of various models) sold, similar for Spectrum, Comomodore 64 less. Amiga's and Atari's weren't for sale until the tail end of the 80s (and even then, Amiga had sold just ~ 400K between 1988-1990). All together around looks like in in 5 households had a computer, and the distribution favored higher income ones - in working class areas much fewer would. Before 1987 even less.