Ooh this is interesting, I think it’s cultural too, for example Matilda is definitely fairly popular here and with the pet form Tilly after years of disappearing, Olive isn’t popular but Olivia definitely is very popular now.

I have a theory that when we name our kids we won’t choose a name which reminds us of someone we disliked, so our contemporaries names go out of favour and so the generations names go in cycles.