labored breathing vs shortness of breath

labored breathing

noun
  • Breathing at less than 12 or more than 20 breaths per minute with poor or irregular quality, rhythm, or tidal volume; a sign of respiratory distress. 

shortness of breath

noun
  • difficulty in breathing; dyspnea 

How often have the words labored breathing and shortness of breath occurred in a corpus of books? (source: Google Ngram Viewer )