cumulate vs keep in reserve

cumulate

verb
  • To accumulate; to amass. 

  • To be accumulated. 

adj
  • accumulated, agglomerated, amassed 

noun
  • An igneous rock formed by the accumulation of crystals from a magma either by settling or floating. 

keep in reserve

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