appertain vs correlate

appertain

verb
  • To belong to or be a part of, whether by right, nature, appointment, or custom; to relate to. 

  • To belong as a part, right, possession, attribute, etc. 

correlate

verb
  • To compare things and bring them into a relation having corresponding characteristics. 

  • To be related by a correlation; to be correlated. 

noun
  • Either of a pair of things related by a correlation; a correlative. 

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