What is the total average for McCain% of 55.0% and Obama# higher than 3,487?
CREATE TABLE "by_county" (
  "county" text,
  "obamapct" text,
  "obamanum" real,
  "mc_cainpct" text,
  "mc_cainnum" real,
  "total" real
);
SELECT AVG("total") FROM "by_county" WHERE "mc_cainpct"='55.0%' AND "obamanum">'3,487';