user: ### NOW ANSWER:
Question: What is the average Laps, when Grid is 15?
Columns: ['Rider', 'Manufacturer', 'Laps', 'Time', 'Grid']
Types: ['text', 'text', 'real', 'text', 'real']
Sample row: ['Alvaro Bautista', 'Aprilia', 26.0, '44:34.257', 2.0]
SQL:

assistant: SELECT AVG("Laps") FROM "Table" WHERE "Grid" = 15.0;