dirty laundry vs ironing

dirty laundry

noun
  • A clothes hamper or other container in which soiled laundry is placed. 

  • Used other than figuratively or idiomatically: see dirty, laundry. 

  • Unflattering or embarrassing facts, or questionable activities that one wants to remain secret, but which someone else may use as blackmail. 

ironing

noun
  • Laundry that has been washed and is ready to be ironed. 

  • The act of pressing clothes with an iron. 

  • Laundry that has recently been ironed. 

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