keep safe vs look after

keep safe

look after

verb
  • To follow with the eyes; to look in the direction of (someone or something departing). 

  • To care for; to keep safe. 

  • To seek out, to look for. 

  • To have as one's business; to manage, be responsible for. 

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