excretion vs offloading

excretion

noun
  • The process of removing or ejecting material that has no further utility, especially from the body; the act of excreting. 

  • Something excreted in that manner, especially urine or feces. 

offloading

noun
  • The act by which something is offloaded. 

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