evaporation vs humidity

evaporation

noun
  • The process in which all or a portion of liquid (in a container) is turned into vapour, in order to increase the concentration of solid matter in the mixture. 

  • The process of a liquid converting to the gaseous state. 

humidity

noun
  • The amount of water vapour in the air. 

  • Dampness, especially that of the air. 

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