It's just % of bigrams that appear in Google's sample of books. [1] Not especially meaningful, I admit! [1] https://books.google.com/ngrams/info https://books.

It's just % of bigrams that appear in Google's sample of books. [1] Not especially meaningful, I admit! [1] https://books.google.com/ngrams/info https://books.google.com/ngrams/info