toddler vs yearling

toddler

noun
  • A young child who has started walking but not fully mastered it, typically between one and three years old. 

yearling

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

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

  • A sophomore at West Point military academy. 

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