It appears I have at least 61 aloha shirts. (Plus a bowling shirt that gets a spot in the rotation.) So I can go 12 workweeks without wearing the same shirt to the office twice. Possibly longer, what with holidays and vacation days!
Photo of my closet to follow. It's still on my camera. Oh, and I think I've got an extra shirt at the office so the count's up to 63 shirts at least. Five of them have flamingos.