Royce is taking violin lessons. The instructor charges an initial fee and an hourly fee. The amount Royce pays based on the length of his lesson is shown in the graph below. What is the instructor’s hourly fee?

A graph titled Cost of Royce's Violin lesson has length of lesson (hours) on the x-axis and cost (dollars) on the y-axis. A line goes through points (2, 52), (3, 67), (4, 82) and (5, 97).
$15 per hour
$22 per hour
$26 per hour
$37 per hour