ante meridiem vs p.m.

ante meridiem

adv
  • before noon, in the morning. 

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 ante meridiem and p.m. occurred in a corpus of books? (source: Google Ngram Viewer )