genticide vs regicide

genticide

noun
  • The killing of a race or nation of people; the slaughter of an ethnic group; a genocide. 

  • The killing of a kinsman or kinswoman; the murder of a blood relative. 

regicide

noun
  • The killing of a king. 

  • One who kills a king. 

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