mortality vs pale rider

mortality

noun

  • Death. 

  • The number of deaths per given unit of population over a given period of time. 

  • Deaths resulting from an event (such as a war, epidemic or disaster). 

  • The state of being susceptible to death. 

pale rider

noun

  • Death, the Grim Reaper or angel of death; and one of the Four Horsemen of the Apocalypse. 

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