What is the total Decile with Waikanae Area?
CREATE TABLE "kapiti_coast_district" (
  "name" text,
  "years" text,
  "gender" text,
  "area" text,
  "authority" text,
  "decile" real,
  "roll" real
);
SELECT SUM("decile") FROM "kapiti_coast_district" WHERE "area"='waikanae';