grassroots vs predominant

grassroots

adj
  • Of, or relating to people or society at the local level, particularly in politics, social movements, etc.; of the grass roots. 

predominant

adj
  • Significant or important; dominant. 

  • Common or widespread; prevalent. 

noun
  • A subdominant. 

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