conscientious vs salt of the earth

conscientious

adj
  • Thorough, careful, or vigilant in one’s task performance. 

  • Influenced by conscience; governed by a strict regard to the dictates of conscience, or by the known or supposed rules of right and wrong (said of a person). 

salt of the earth

noun
  • A decent, dependable, unpretentious person. 

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