keep under vs repress

keep under

verb
  • To hold in subjection; hence, to oppress. 

repress

verb
  • To forcefully prevent an upheaval from developing further. 

  • To check; to keep back. 

  • To press again. 

noun
  • A record pressed again; a repressing. 

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