Cognomen 柏金 (柏金 
, Birkin 
) , in the entire world, is quite a rare last name. The surname 柏金 is characteristic of the United Kingdom, where it is quite a rare surname, Australia, where it is a rare surname, and New Zealand. In absolute terms, it most frequently occurs in the United Kingdom, China, and Australia. Likewise, 柏金 is the forename as well as the last name.