murder in the first degree vs second-degree murder

murder in the first degree

noun
  • Synonym of first-degree murder 

second-degree murder

noun
  • An act that constitutes the crime of second-degree murder. 

  • The criminal offence of murder in a form defined as less serious than first-degree murder; the precise distinction may vary by jurisdiction but typically involves second-degree murder being intentional but not premeditated. 

How often have the words murder in the first degree and second-degree murder occurred in a corpus of books? (source: Google Ngram Viewer )