pallium vs vestment

pallium

noun
  • A woolen liturgical vestment resembling a collar and worn over the chasuble in the Western Christian liturgical tradition, conferred on archbishops by the Pope, equivalent to the Eastern Christian omophorion. 

  • The mantle of a mollusc. 

  • A large cloak worn by Greek philosophers and teachers. 

  • The cerebral cortex. 

vestment

noun
  • Any of the special articles of clothing worn by members of the clergy etc., especially a garment worn at the celebration of the Eucharist. 

  • Clothing. 

  • A robe, gown, or other article of clothing worn as an indication of office. 

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