What's the Year Average that has a Power of BHP (KW) and Trim of LS/2LT?
CREATE TABLE "engines" (
  "year" real,
  "trim" text,
  "engine" text,
  "power" text,
  "torque" text,
  "epa_2008_city" text
);
SELECT AVG("year") FROM "engines" WHERE "power"='bhp (kw)' AND "trim"='ls/2lt';