harass vs pick on

harass

verb
  • To annoy (someone) frequently or systematically; to pester. 

  • To persistently bother (someone, or a group of people) physically or psychologically when such behaviour is illegal and/or unwanted, especially over an extended period. 

  • To trouble (someone, or a group of people) through repeated military-style attacks. 

  • To put excessive burdens upon (someone); to subject (someone) to anxieties. 

pick on

verb
  • To bully, harass, or make fun of a victim; to bother or harass. 

  • To select (a person) for a task, etc. 

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