Whitman's sampler vs mixed bag

Whitman's sampler

noun
  • A diverse collection. 

mixed bag

noun
  • Any bag containing a mixture of something. 

  • A group of entities with few characteristics in common. 

  • Something tending to have both good and bad results or characteristics; something having a mixture of advantages and disadvantages. 

How often have the words Whitman's sampler and mixed bag occurred in a corpus of books? (source: Google Ngram Viewer )