continuative vs perpetual

continuative

adj
  • Of or pertaining to continuation. 

  • durative. 

noun
  • a durative. 

  • Something that causes a continuation. 

perpetual

adj
  • Continuing; uninterrupted. 

  • Set up to be in effect or have tenure for an unlimited duration. 

  • Lasting forever, or for an indefinitely long time. 

  • Flowering throughout the growing season. 

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