accumulative vs summative

accumulative

adj
  • Characterized by accumulation; serving to collect or amass 

  • Having a propensity to amass; acquisitive. 

summative

adj
  • Of, pertaining to, or produced by summation. 

  • Denoting forms of assessment used to quantify educational outcomes. 

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