instructive vs knowledgeful

instructive

adj
  • Conveying knowledge, information or instruction. 

noun
  • A case in the Finnish and Estonian languages. It expresses the means or the instrument used to perform an action. 

knowledgeful

adj
  • Full of knowledge; knowledgeable. 

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