ergative case vs predicative case

ergative case

noun
  • A grammatical case used to indicate the agent of a transitive verb in ergative-absolutive languages. 

predicative case

noun
  • A term that may sometimes be used to describe the case marking a predicative nominative (a noun that renames the subject often following a linking verb), or for the adjective that agrees with it (predicative adjective). 

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