Hanyu vs Putonghua

Hanyu

name
  • Chinese; the Chinese language(s) 

  • A surname from Japanese. 

Putonghua

name
  • Standard Mandarin, the official language of the People's Republic of China; the state-designated national speech of the Han nationality using Beijing pronunciation as the standard pronunciation, Beijing speech as the basic dialect, and the model writing of the modern vernacular prose as the norm for grammar. 

How often have the words Hanyu and Putonghua occurred in a corpus of books? (source: Google Ngram Viewer )