level up vs upsurge

level up

verb
  • To raise to the same level or status; to improve so as to make as good as others. 

  • To progress to the next level of player character stats and abilities, often by acquiring experience points in role-playing games. 

upsurge

verb
  • to surge up, or to become stronger or greater 

noun
  • A sudden strong rise or flow. 

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