Nataraj​ (2007) finds that a 100​% increase in the price of water for heavy users in Santa Cruz caused the quantity of water they demanded to fall by an average of 20​%. ​ (Before the​ increase, heavy users initially paid ​$1.55 per​ unit, but afterwards they paid ​$3.10 per​ unit.) In percentage​ terms, how much did their water expenditure​ (price times ​quantity)long dashwhich is the water​ company's revenuelong dash​change? With the price​ increase, the​ company's revenue changed by .31 nothing​%. ​(Enter your answer rounded to two decimal​ places.)