first reader vs publisher's reader

first reader

noun
  • Synonym of publisher's reader (see reader). 

  • A book for children who are learning to read, usually consisting of pictures and some basic words or phrases. 

publisher's reader

noun
  • Synonym of reader (sense 5: a person employed by a publisher to read works submitted for publication and determine their merits). 

How often have the words first reader and publisher's reader occurred in a corpus of books? (source: Google Ngram Viewer )