changeability vs fluidity

changeability

noun
  • The quality of being changeable; changeableness. 

fluidity

noun
  • The quality of being fluid or free-flowing 

  • A measure of the extent to which something is fluid. The reciprocal of its viscosity. 

  • The state of being fluid rather than viscous 

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