duck soup vs pushover

duck soup

noun
  • Something which is easy; a piece of cake. 

  • Used other than figuratively or idiomatically: see duck, soup. 

pushover

noun
  • Something that is easy to do or accomplish; an easy task. 

  • Someone who is easily swayed or influenced to change his/her mind or comply. 

  • Someone who lets him/herself be picked or bullied on without defending or standing up for him/herself. 

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