equally vs pro rata

equally

adv
  • In equal degree or extent; just as. 

  • Used to link two or more coordinate elements 

  • In an equal manner; in equal shares or proportion; with equal and impartial justice; evenly 

pro rata

adv
  • In proportion to some factor that can be exactly calculated. 

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