last roundup vs pale rider

last roundup

noun
  • Death. 

  • A final gathering of people or items; the final event in a series of events involving a group or organization. 

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 last roundup and pale rider occurred in a corpus of books? (source: Google Ngram Viewer )