dishwasher vs helper

dishwasher

noun
  • Someone who washes dishes, especially one hired to wash dishes in a restaurant. 

  • A European bird, the wagtail. 

  • A machine for washing dishes. 

  • A bird, the restless flycatcher (Myiagra inquieta). 

helper

noun
  • A person who does cleaning and cooking in a family home, or in a market; domestic employee. 

  • That which helps; anything serving to assist. 

  • One who helps; an aide; assistant; auxiliary. 

  • A locomotive that assists a train, usually on steep gradients. 

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