Carthusian vs abbot

Carthusian

noun
  • A member of a Christian contemplative order of monks founded by Bruno of Cologne (St Bruno) in 1084. 

  • A pupil of Charterhouse School (founded in a Carthusian monastery) 

adj
  • Of, or relating to this order. 

abbot

noun
  • The superior or head of an abbey or monastery. 

  • The pastor or administrator of an order, including minor and major orders starting with the minor order of porter. 

  • A layman who received the abbey's revenues, after the closing of the monasteries. 

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