The Mother's Day Birthday Puzzle

Rosalie's little brother Connor was born on May 11, 1997,which was Mother's Day. Mother's Day is the second Sunday of May every year.
By the time he is 80, how many times will Connor's birthday have been on Mother's Day?


.

No one answer?

ding.

thanks guys,but is there any other way to solve it instead of counting every year?

btw,the answer is 12.