lecturer vs proofreader

lecturer

noun
  • A person who gives lectures, especially as a profession. 

  • A member of a university or college below the rank of assistant professor or reader. 

proofreader

noun
  • A person whose occupation is to proofread. 

  • A person who proofreads. 

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