dyspepsia vs tummyache

dyspepsia

noun
  • Any mild disorder of digestion, characterised by stomach pain, discomfort, heartburn and nausea, often following a meal. 

tummyache

noun
  • Any pain in the stomach or abdomen. 

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