ass-kisser vs brown noser

ass-kisser

noun
  • Someone who kisses ass (who acts obsequiously in order to gain another's favor). 

brown noser

noun
  • One who brownnoses (flatters or humors somebody in an obsequious manner for personal gain); one who sucks up; a bootlicker, ass-kisser, sycophant. 

How often have the words ass-kisser and brown noser occurred in a corpus of books? (source: Google Ngram Viewer )