beleaguer vs pester

beleaguer

verb
  • To vex, harass, or beset. 

  • To besiege; to surround with troops. 

  • To exhaust. 

pester

verb
  • To bother, harass, or annoy persistently. 

noun
  • A bother or nuisance. 

How often have the words beleaguer and pester occurred in a corpus of books? (source: Google Ngram Viewer )