infant vs sweet sixteen

infant

noun
  • A minor. 

  • A very young human being, from conception to somewhere between six months and two years of age after birth, needing almost constant care and attention. 

sweet sixteen

noun
  • sixteen 

  • A girl's sixteenth birthday, or sixteenth-birthday party and a related coming of age party. 

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