Chinese foot vs Hong Kong foot

Chinese foot

noun
  • A chi, a traditional Chinese unit of distance based on the human forearm, now standardized variously as (Mainland China) ¹/₃ or (Taiwan) ¹⁰/₃₃ of a meter. 

Hong Kong foot

noun
  • A chek, the Hong Kong variant of the Chinese foot now standardized as 0.371475 meters. 

  • Athlete's foot. 

How often have the words Chinese foot and Hong Kong foot occurred in a corpus of books? (source: Google Ngram Viewer )