diversity vs fluctuation

diversity

noun
  • Equal-opportunity inclusion. 

  • The quality of being diverse or different; difference or unlikeness. 

  • A variety; diverse types or examples. 

fluctuation

noun
  • A wavering; unsteadiness. 

  • In medicine, a wave-like motion or undulation of a fluid in a natural or abnormal cavity (e.g. pus in an abscess), which is felt during palpation or percussion. 

  • A motion like that of waves; a moving in this and that direction. 

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