rookie vs yearling

rookie

noun
  • An inexperienced recruit, especially in the police or armed forces. 

  • A type of firecracker, used by farmers to scare rooks. 

  • A novice. 

  • An athlete either new to the sport or to a team or in his first year of professional competition, especially said of baseball, basketball, hockey and American football players. 

adj
  • non-professional; amateur 

yearling

noun
  • A sophomore at West Point military academy. 

  • A racehorse that is considered to be one year old until a subsequent January 1st. 

  • An animal that is between one and two years old; one that is in its second year (but not yet two full years old). 

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