heffalump vs salad dodger

heffalump

noun
  • A clumsy or overweight person. 

  • (A child's name for) an elephant. 

  • Something that is elusive. 

salad dodger

noun
  • An overweight person. 

  • One who does not normally eat salad. 

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