pick up on vs size up

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. 

size up

verb
  • To evaluate; to estimate or anticipate the magnitude, difficulty, or strength of something. 

  • To wear a larger size of clothing. 

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