bit part vs leading lady

bit part

noun
  • A minor role, generally not assigned a name. 

leading lady

noun
  • A woman who does or can play the lead role in a movie, play or other production; a woman who frequently plays such roles. 

  • The type of conventionally beautiful and approachable woman who is perceived as being capable of playing female lead roles in movies or other productions. 

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