close out vs keep on

close out

verb
  • To terminate; to call the end of. 

  • To terminate a computer program. 

  • To make trades offsetting an existing position, leaving the trader with a neutral position. 

  • Of a wave, to break all at once, instead of progressively along its length. 

  • To exclude by blocking all opportunities to enter or join. 

  • To seal off. 

  • Synonym of close (“to make a sale”) 

keep on

verb
  • To persist or continue. 

  • To cause or allow to remain in the on or open position. 

  • To cause or allow to remain in an existing position. 

  • To persist in talking about a subject to the annoyance of the listener. 

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