attainment vs necessitation

attainment

noun
  • That which is attained, or obtained by exertion. 

  • The act of attaining; the act of arriving at or reaching; the act of obtaining by exertion or effort. 

necessitation

noun
  • Necessity, understood as a logical or other philosophical principle, or as a law or force of nature. 

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