probable vs simple as ABC

probable

adj
  • Supporting, or giving ground for, belief, but not demonstrating. 

  • Likely or most likely to be true. 

  • Likely to happen. 

noun
  • A person who is likely to appear or do a certain thing. 

  • Something that is likely. 

simple as ABC

How often have the words probable and simple as ABC occurred in a corpus of books? (source: Google Ngram Viewer )