marked vs plain as day

marked

adj
  • Clearly evident; noticeable; conspicuous. 

  • Singled out; suspicious; treated with hostility; the object of vengeance. 

  • Having a secret mark on the back for cheating. 

  • In police livery, as opposed to unmarked. 

  • Distinguished by a positive feature. 

  • Having a visible or identifying mark. 

plain as day

adj
  • Very clear and evident. 

How often have the words marked and plain as day occurred in a corpus of books? (source: Google Ngram Viewer )