contain vs keep back

contain

verb
  • To put constraints upon; to restrain; to confine; to keep within bounds. 

  • To include as a part. 

  • To hold inside. 

  • To have as an element or subset. 

keep back

verb
  • To restrict or restrain. 

  • To hold back; to refuse to give or share. 

  • To prevent (a pupil) from advancing in a course. 

  • To stay back; to refrain from approaching. 

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