Rare, but how rare?

Amy • Mom to 4 beautiful girls. 3/3/10, 4/27/14, 4/8/17, 3/7/19.
I know it's super uncommon these days to be told you're having a girl and then you end up having a boy. I was just curious if anyone had an experience like that or knew someone who did? And if ultrasound pictures are available that's fun too. (: