proletariat vs rank and file

proletariat

noun
  • The lowest class of society; also, the lower classes of society generally; the masses. 

  • Wage earners collectively, excluding salaried workers; people who own no capital and depend on their labour for survival; the working class, especially when seen as engaged in a class struggle with the bourgeoisie (“the capital-owning class”). 

  • The lowest class of citizens, who had no property and few rights, and were regarded as contributing only their offspring to the state. 

rank and file

noun
  • Members of an organization who are not in leadership positions. 

  • Enlisted soldiers in a military organization, as would be arrayed in a grid pattern with ranks and files. 

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