daft as a brush vs wacko

daft as a brush

adj

  • Tending to do or say silly things. 

wacko

adj

  • Amusingly eccentric or irrational. 

noun

  • An amusingly eccentric or irrational person. 

How often have the words daft as a brush and wacko occurred in a corpus of books? (source: Google Ngram Viewer )