dyspepsia vs pyrosis

dyspepsia

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

pyrosis

noun
  • A burning sensation in the chest due to reflux of stomach contents in the esophagus. 

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