What is your source for the 15% number? In SF, UberX costs the same as taxis per mile, has no tip but a higher minimum, and surges regularly to 1.75x or more ev

What is your source for the 15% number? In SF, UberX costs the same as taxis per mile, has no tip but a higher minimum, and surges regularly to 1.75x or more every time there is high demand, such as on weekends