What's the size of Centerville in 89 Wayne county with an IHSAA class of AA in the year before 1974?
CREATE TABLE "membership" (
  "school" text,
  "location" text,
  "mascot" text,
  "size" real,
  "ihsaa_class" text,
  "num_county" text,
  "year_joined" real,
  "previous_conference" text
);
SELECT "size" FROM "membership" WHERE "year_joined"<1974 AND "ihsaa_class"='aa' AND "num_county"='89 wayne' AND "school"='centerville';