CREATE TABLE table_22186 ("Year" FLOAT, "Car number" FLOAT, "Start" FLOAT, "Qual. speed" TEXT, "Speed rank" FLOAT, "Finish" FLOAT, "Laps completed" FLOAT, "Laps led" FLOAT, "Race status" TEXT, "Chassis" TEXT)

What year(s) was the race status piston?
SELECT "Year" FROM table_22186 WHERE "Race status" = 'Piston'
SELECT "Year" FROM "table_22186" WHERE "Race status" = 'Piston'