breakfast cereal vs cornflake

breakfast cereal

noun
  • A food made from processed grains, such as maize, oats, wheat or rice, usually eaten for breakfast with milk and sometimes sugar. 

cornflake

noun
  • A toasted flake of maize used as breakfast cereal. 

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