pushchair vs quad bike

pushchair

noun
  • A small carriage in which a baby or child is pushed around; a stroller or baby buggy 

quad bike

noun
  • A small off-road four-wheeled powered vehicle, especially of a design derived from a motorcycle, usually used for recreation or farm work. 

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