bowel movement vs passing/discharging/excreting feces

bowel movement

noun

  • The discharge of feces from the body, an act of defecation. 

  • The feces thus produced. 

passing/discharging/excreting feces

How often have the words bowel movement and passing/discharging/excreting feces occurred in a corpus of books? (source: Google Ngram Viewer )