outstripping vs surpassing

outstripping

noun
  • The act or process of something being outstripped. 

surpassing

noun
  • The act or process by which something is surpassed; a bettering. 

adj
  • Becoming superior to others; becoming excellent; exceptional; exceeding. 

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