CREATE TABLE table_78436 ("Driver" TEXT, "Constructor" TEXT, "Laps" FLOAT, "Time/Retired" TEXT, "Grid" FLOAT)

What is the average Laps for a grid smaller than 17, and a Constructor of williams - bmw, driven by jenson button?
SELECT AVG("Laps") FROM table_78436 WHERE "Grid" < '17' AND "Constructor" = 'williams - bmw' AND "Driver" = 'jenson button'
SELECT AVG("Laps") FROM "table_78436" WHERE "Constructor" = 'williams - bmw' AND "Driver" = 'jenson button' AND "Grid" < '17'