Some of you may have seen this before, but if you are curious about the distribution of surnames in the USA, you can head over to the US Census Bureau and check these records out:
Frequently Occurring First Names and Surnames From the 1990 Census
It’ll give you an idea, at least as of 1990, on how popular certain surnames (and first names, let’s not forget first names) are. There might be more people that share your unique last name that you thought.