back onto vs give over

back onto

verb
  • To overlook something from the rear. 

  • To reverse a vehicle onto something. 

give over

verb
  • To devote or resign to a particular purpose or activity; to yield completely. 

  • To give up; abandon; stop. 

  • To quit, to abandon. 

  • To entrust (something) to another. 

How often have the words back onto and give over occurred in a corpus of books? (source: Google Ngram Viewer )