bicolour vs mottled

bicolour

adj
  • Having two colours 

noun
  • A flower, cat etc., that has two colours. 

  • A flag with such colours, consisting of two stripes that are either vertical or horizontal. 

mottled

adj
  • Colored in patches; spotted. 

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