immobility vs sluggishness

immobility

noun
  • The quality of not moving. 

  • The state or condition of being unable to change one's location, move or be moved. 

sluggishness

noun
  • The property of being sluggish, unable or unwilling to act quickly. 

  • The state of economic decline, inactivity, slow or subnormal growth. 

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