keep under wraps vs stash

keep under wraps

stash

verb
  • To hide or store away for later use. 

noun
  • Clothing or other items branded with a particular university club or society's logo. 

  • A place where drugs are stored. 

  • A collection of yarn or other materials not yet allocated to any particular craft project. 

  • mustache 

  • A collection, sometimes hidden; a reserve. 

How often have the words keep under wraps and stash occurred in a corpus of books? (source: Google Ngram Viewer )