few cards shy of a full deck vs non compos mentis

few cards shy of a full deck

adj

  • mentally deranged; demented; insane. 

non compos mentis

adj

  • Insane; not of sound mind; not in control of oneself. 

How often have the words few cards shy of a full deck and non compos mentis occurred in a corpus of books? (source: Google Ngram Viewer )