PM vs p.m.

PM

verb
  • To project manage. 

  • To send a private message to (a participant in a chat room, etc.). 

p.m.

adv
  • after death 

  • after noon (used after a time to indicate it is between noon and midnight, i.e., in the afternoon, evening or night as opposed to the morning) 

How often have the words PM and p.m. occurred in a corpus of books? (source: Google Ngram Viewer )