Pa vs folks

Pa

noun
  • A short form of grandpa; grandfather. 

  • Father, dad, papa. 

folks

noun
  • People in general; everybody or anybody. 

  • The members of one's immediate family, especially one's parents 

  • The police. 

  • Late 19th and early 20th century migrants to California from Iowa and other parts of the Midwestern United States. 

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