centralization vs concentration

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 

concentration

noun
  • The act, process or product of reducing the volume of a liquid, as by evaporation. 

  • The proportion of a substance in a whole. 

  • The act or process of removing the dress of ore and of reducing the valuable part to smaller compass, as by currents of air or water. 

  • The direction of attention to a specific object. 

  • A field or course of study on which one focuses, especially as a student in a college or university. 

  • The amount of solute in a solution measured in suitable units (e.g., parts per million (ppm)) 

  • The matching game pelmanism. 

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