How many vocal parts are there when the year of songs original release date as listed in rock band 3 was 2000?
CREATE TABLE "track_listing" (
  "song_title" text,
  "artist" text,
  "year_year_of_songs_original_release_as_listed_in_rock_band_3" real,
  "genre" text,
  "keyboard_support" text,
  "vocal_parts" real,
  "nintendo_ds_setlist" text
);
SELECT MIN("vocal_parts") FROM "track_listing" WHERE "year_year_of_songs_original_release_as_listed_in_rock_band_3"=2000;