8, 10, 12, 14, 17, 19, 21 will cover 95% of asian car repairs.
8, 10, 12, 14(?), 15, 18 is a european thing and some domestics have picked up the banner as well.
I've never used a 9mm or 11mm. I've never seen anything manufactured to use it. 7/16 and 11mm are just close enough to round the...