Me, DH and DS, I don't know, but I do know DD's and my sister's and they are within 4 points of each other.
DS I'm guessing is similar to DD as they are such similar kids and based on some of his achievement scores - and I've also taken all that to mean mine is probably the same as theirs too.
And just to keep the assumptions going, I reckon that DH is around the same too smile
OP, you should just test if you're curious!