endorse vs sign off on

endorse

noun
  • A diminutive of the pale, usually appearing in pairs on either side of a pale. 

verb
  • To report (a symptom); to describe. 

  • To write one's signature on the back of a cheque, or other negotiable instrument, when transferring it to a third party, or cashing it. 

  • To express support or approval, especially officially or publicly. 

  • To give an endorsement. 

sign off on

How often have the words endorse and sign off on occurred in a corpus of books? (source: Google Ngram Viewer )