encourage vs pester

encourage

verb
  • To foster, give help or patronage 

  • To mentally support; to motivate, give courage, hope or spirit. 

  • To spur on, strongly recommend. 

pester

verb
  • To bother, harass, or annoy persistently. 

noun
  • A bother or nuisance. 

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