useless as tits on a boar hog vs vacuous

useless as tits on a boar hog

adj

  • Ineffectual, pointless. 

vacuous

adj

  • Empty; void; lacking meaningful content. 

  • Showing a lack of thought or intelligence; vacant. 

How often have the words useless as tits on a boar hog and vacuous occurred in a corpus of books? (source: Google Ngram Viewer )