9 to 5 vs working day

9 to 5

noun
  • The workday itself (the period of the day between 9 am and 5 pm). 

  • A day job, especially at a large company, emphasizing banality. 

  • One who works in a job from 9 am to 5 pm. 

working day

noun
  • The part of a day in which work is done; the number of hours one must work per day for a specified wage. 

  • Any of those days of a week on which work is done, officially Monday to Friday in many countries (even though many people work on weekends). 

How often have the words 9 to 5 and working day occurred in a corpus of books? (source: Google Ngram Viewer )