There are no common Thai surnames. Surnames were largely introduced to Thai culture only by the 1913 Surname Act. The law does not allow one to create any surname that is duplicated with any existing surnames. Under Thai law, only one family can create any given surname: any two people of the same surname must be related, and it is very rare for two people to share the same full name. In one sample of 45,665 names, 81% of family names were unique.