In his book 10 Rules of Writing, Elmore Leonard offered a rule about exclamation points. He stated, “You are allowed no more than two or three per 100,000 words of prose.” Leonard was prolific. He wrote more than 40 novels in his career, totaling 3.4 million words. If he had followed his own advice, he would have used only 102 exclamation points in his entire career. In practice, he used 1,651. That’s 16 times as many as he recommended! But before you start thinking that Leonard was a secret exclamation-point fanatic, consider the chart below.
— Adapted from Nabokov’s Favorite Word Is Mauve: What the Numbers Reveal About the Classics, Bestsellers, and Our Own Writing