additional vs subalternate

additional

adj
  • Supplemental or added to something. 

noun
  • Something added. 

subalternate

adj
  • Subaltern; inferior; subordinate. 

  • Succeeding by turns; successive. 

noun
  • A particular proposition, as opposed to a universal one. 

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