leading vs prima

leading

adj
  • Ranking first. 

  • Providing guidance or direction. 

  • Occurring in advance; preceding. 

noun
  • Vertical space added between lines; line spacing. 

  • An act by which one is led or guided. 

prima

adj
  • most important 

How often have the words leading and prima occurred in a corpus of books? (source: Google Ngram Viewer )