cake walk vs kid's stuff

cake walk

noun
  • A type of dance originating in the United States in the 19th century. 

  • From the mid 1900s, a game at a fair or party in which people walk around a numbered circle along to music. When the music is stopped, the caller draws a number from a jar and whoever is standing on or closest to that number wins a cake. 

  • Something extremely easy. 

kid's stuff

How often have the words cake walk and kid's stuff occurred in a corpus of books? (source: Google Ngram Viewer )