pick up on vs take in

pick up on

verb
  • To notice, observe, learn, or understand, especially something otherwise overlooked. 

  • To adopt a practice in which others already engage. 

  • To continue or build upon (for example, a task, analysis, or narrative), beginning from a point at which someone has previously stopped. 

take in

verb
  • To absorb or comprehend. 

  • To allow a person or an animal to live in one's home. 

  • To receive (goods) into one's home for the purpose of processing for a fee. 

  • To enjoy or appreciate. 

  • To deceive; to hoodwink. 

  • To tighten (a belaying rope). (Also take up.) 

  • To shorten (a garment) or make it smaller. 

  • To attend a showing of. 

  • To reef. 

How often have the words pick up on and take in occurred in a corpus of books? (source: Google Ngram Viewer )