CHiP vs locker

CHiP

noun
  • An officer of the California Highway Patrol 

locker

noun
  • A customs officer who guards a warehouse. 

  • A locking differential. 

  • A type of storage compartment with a lock, usually used to store personal possessions for public use, such as in schools, railway stations, place of work, gyms, sports centers. 

  • One who locks something. 

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