According to Social Security records, the most common Scottish Macs are MacDonald (57 thousand), MacKenzie (18 thousand) and MacKay (11 thousand). Any telephone directory will reveal many others, but I suspect that few people have encountered the following Macs and their appropriate occupations:
Word Ways: Vol. 16
, Article 15.
Available at: http://digitalcommons.butler.edu/wordways/vol16/iss1/15