highland vs promontory

highland

noun
  • A high area; land that is higher than surrounding areas. 

promontory

noun
  • A high point of land extending into a body of water, headland; cliff. 

  • A rounded elevation in the tympanum of the ear. 

  • A projection on the sacrum. 

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