maturation vs upgrowth

maturation

noun
  • The process of becoming mature. 

  • The process of maturating, or suppurating fully. 

  • The process of differentiation that produces the adult form of an organism. 

upgrowth

noun
  • The process or result of growing up; progress; development. 

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