Given the task definition and input, reply with output. In this task, you're given a statement, further information available on a particular linked term from the statement, and a question. Your job is to generate the answer to the question by using the information provided. If there is no clear answer obtainable, output 'none'.

Context: he made four Indy Lights starts in 1997 with a best finish of 11th at Nazareth Speedway. Link Information: Nazareth 100 (Dirt).- 1968 Al Unser
- 1969 Mario Andretti
- 1982 Keith Kauffman

DeVilbiss Superfinish 200.- 1996 Jack Sprague (Race shortened to 152 laps/152 miles due to rain)
NAPA AutoCare 200.- 1997 Jack Sprague Question: How many races had been run at Nazareth Speedway by the year Bingham finished 11th there during Indy Lights?
Answer: 5