decennary vs decimation

decennary

noun
  • A decennium: a period of ten years. 

adj
  • Decennial: of or related to a ten-year period. 

decimation

noun
  • The killing or punishment of every tenth person, usually by lot. 

  • A digital signal-processing technique for reducing the number of samples in a discrete-time signal; downsampling 

  • The creation of a new sequence comprising only every nth element of a source sequence. 

  • The killing or destruction of any large portion of a population. 

  • A tithe or the act of tithing. 

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