nurse practitioner vs practical nurse

nurse practitioner

noun
  • A professional nursing designation recognized in some jurisdictions, denoting an individual who is fully qualified as a nurse and who has additional qualifications and authorization to provide diagnoses and/or treatments, including writing prescriptions . 

practical nurse

noun
  • A person who is certified to provide custodial care such as help in walking, bathing, and feeding. 

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