apparent vs plain as a haystack

apparent

adj
  • Clear or manifest to the understanding; plain; evident; obvious; known; palpable; indubitable. 

  • Capable of being seen, or easily seen; open to view; visible to the eye, eyely; within sight or view. 

  • Appearing to the eye or mind (distinguished from, but not necessarily opposed to, true or real); seeming. 

plain as a haystack

adj
  • Extremely clear and plain to see. 

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