My maternal GGM was one of 10, she herself had 6, but one died as a baby. One of hers (my DM) had 4, 2 others had 2 each.
OTOH my paternal GM had just one - from all I gather a very difficult birth was enough to put her off having any more!
My dd1 has 3 (3rd was a ‘surprise’), dd2 won’t be having any, out of choice.
Interestingly, for reasons of space, the reception class at the Gdcs’ primary used to be housed in their pre-school, a 15 minute walk away. But falling numbers have meant that there was room in the main building for reception, when the youngest Gdc started last year.
Not sure why numbers have fallen - unless it’s crazy property prices driving people away! A nice area of outer Oxford but by no means anything like the most expensive.