ahead of vs outstripping

ahead of

prep
  • Preceding. 

  • In front of. 

  • Having made more progress than. 

  • In the future of. 

  • In advance of. 

outstripping

noun
  • The act or process of something being outstripped. 

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