interrelated vs relational

interrelated

adj
  • Having a mutual or reciprocal relation or parallelism; correlative. 

relational

adj
  • Relating to relations. 

  • Friendly and peaceful. 

  • Dealing with the whole of human relations and their social context, rather than an independent and private space. 

  • Of a database technology using tables and the principles set forth by Dr. Edgar F. Codd. (Contrary to popular notion, "relation" in this context refers to tables, and not linkages.) 

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