CUKC(s) = Citizen(s) of the United Kingdom and Colonies = Anyone who was born in the UK or a British possession (e.g. HK) before 1 Jan. 1983
BDTC(s) = British Dependent Territories Citizen(s) = People who were born in a 'British Dependent Territory' (e.g. HK from 1 Jan. 1983 to 30 Jun. 1997) on or after 1 Jan. 1983