dotage vs superannuation

dotage

noun
  • Decline in judgment and other cognitive functions, associated with aging; senility. 

  • Fondness or attentiveness, especially to an excessive degree. 

  • Foolish utterance(s); drivel. 

superannuation

noun
  • The condition or of being superannuated; old age or obsolescence. 

  • A retirement benefit fund, an accumulation of regular deductions from one′s wage or salary while employed and similar regular contributions from the employer, usually administered by an independent entity; a pension. 

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