cultivate vs worsen

cultivate

verb
  • To turn or stir soil in preparation for planting. 

  • To nurture; to foster; to tend. 

  • To grow plants, notably crops. 

worsen

verb
  • To make worse; to impair. 

  • To become worse; to get worse. 

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