as straight as a die vs matter-of-fact

as straight as a die

matter-of-fact

adj
  • lacking emotion or colour 

  • of, or relating to facts only; literal, realistic 

  • straightforward, blunt, frank; treating the situation as normal; not embarrassed, coy, or dramatic. 

How often have the words as straight as a die and matter-of-fact occurred in a corpus of books? (source: Google Ngram Viewer )