rejuvenation vs upturn

rejuvenation

noun
  • The process of producing beneficial changes. 

  • The process of rendering young again. 

upturn

noun
  • an upward turn or trend, especially in business activity or profit 

verb
  • to turn (something) up or over 

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