inflate vs step up

inflate

verb
  • To enlarge an object by pushing air (or a gas) into it; to raise or expand abnormally 

  • To decompress (data) that was previously deflated. 

  • To swell; to puff up. 

  • To enlarge by filling with air (or a gas). 

step up

verb
  • To increase, augment, or advance, especially by one or more steps. 

  • To assume or take responsibility. 

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