A1 vs top-flight

A1

adj
  • In excellent or top condition. 

  • First-class. (Compare A 2 and A 3, which are inferior grades.) 

  • In good health. 

noun
  • Under the International Union of Railways ("UIC") classification system, a steam locomotive that has two coupled driving wheels followed by two trailing wheels, with no leading wheels; also called an 0-2-2. 

top-flight

adj
  • Of the highest rank, or peak of excellence 

  • In the highest division 

How often have the words A1 and top-flight occurred in a corpus of books? (source: Google Ngram Viewer )