desegregate vs insulate

desegregate

verb
  • To the end segregation of (something). 

insulate

verb
  • To separate a body or material from others, e.g. by non-conductors to prevent the transfer of electricity, heat, etc. 

  • To separate, detach, or isolate. 

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