centralization vs devolution

centralization

noun
  • The act or process of centralizing, or the state of being centralized; the act or process of combining or reducing several parts into a whole 

devolution

noun
  • A rolling down. 

  • A descent, especially one that passes through a series of revolutions, or by succession 

  • Degeneration (as opposed to evolution). 

  • The transfer of some powers and the delegation of some functions from a central government to local government (e.g. from the U.K. parliament to Scottish parliament and Welsh assembly). 

  • The transference of a right to a successor, or of a power from one body to another. 

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