ameliorate vs injure

ameliorate

verb
  • To make better, or improve, something perceived to be in a negative condition. 

  • To become better; improve. 

injure

verb
  • To damage or impair. 

  • To wound or cause physical harm to a living creature. 

  • To do injustice to. 

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