Johnny has a math test on Friday, an English test on Tuesday, and a social studies quiz on Wednesday. Over the weekend, he read 20 books. He needed to read 5 books for his English test and 2 books for his social studies quiz. A week later, Johnny received a 92 on his math test, 84 on his English test, and a 90 on his social studies quiz. What percent of books did Johnny read that were for social studies? Round to the nearest whole number (percentage). Do not include % in your answer. For example, if the answer is 19%, enter 19.