freshman vs jaffy

freshman

noun
  • A person (of either sex) entering the first year of an institution, especially a high school (ninth grade for US and Canada, grade 7 for Philippines), a university, or legislative body. 

jaffy

noun
  • A person in their first year at an institution, primarily a university. 

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