largely vs on average

largely

adv
  • For the most part; mainly or chiefly. 

  • In a widespread or large manner. 

  • On a large scale; amply. 

on average

prep
  • Expressed as a measure of central tendency (usually the arithmetic mean). 

  • Usually, typically; as a rule; as often as not. 

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