How many Joint Music Awards were there with a RTHK of 1, in a Year before 2006?
CREATE TABLE "major_awards" (
  "year" real,
  "mrhma" text,
  "usca" text,
  "rthk" text,
  "joint_music_award" text,
  "total" real
);
SELECT "joint_music_award" FROM "major_awards" WHERE "year"<2006 AND "rthk"='1';