The famously spare Hemingway used 80 words ending in -ly per 10,000 words of prose; JK Rowling uses 140 adverbs per 10,000 words, and EL James uses 155.
The stats come from a new book called Nabokov's Favorite Word Is Mauve: What the Numbers Reveal About the Classics, Bestsellers, and Our Own Writing, a data-driven look at prose that plumbs the new, massive corpuses of digitized books to make quantitative — rather than the traditional qualitative — statements about our literary habits.
In the novel The Hobbit, J.R.R. Tolkien used the word "she" only once. In The Prime of Miss Jean Brodie, however, she relative to he is used 79% of the time, the highest ratio of the classics surveyed. Female authors are very strongly represented on that side of the curve, let me tell you. And male authors do the "he" far more, in relative terms, than female authors do the "she."
You also will learn from this book that David Brooks starts more sentences with "The" than any other word, whereas for Paul Krugman that place of honor goes to "But." And, for better or worse, Krugman uses far less anaphora.
Number of -ly adverbs per 10,000 words
[Tyler Cowen/Marginal Revolution]