hobby vs slimnastics

hobby

noun
  • An activity that one enjoys doing in one's spare time. 

  • Any of four species of small falcons in the genus Falco, especially Falco subbuteo. 

  • An extinct breed of horse native to the British Isles, also known as the Irish Hobby 

slimnastics

noun
  • A form of athletic exercise intended to promote weight loss. 

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