don't forget to write vs sayonara

don't forget to write

intj

  • Addressed to someone whose departure is permanent or for a long time 

sayonara

intj

  • Goodbye, adieu. 

noun

  • An utterance of sayonara, the wishing of farewell to someone. 

How often have the words don't forget to write and sayonara occurred in a corpus of books? (source: Google Ngram Viewer )