List the total number of constitutional amendments for a five cent gasoline tax bill.
CREATE TABLE "1928_general_election" (
  "meas_num" real,
  "passed" text,
  "yes_votes" real,
  "no_votes" real,
  "pct_yes" text,
  "const_amd" text,
  "type" text,
  "description" text
);
SELECT COUNT("const_amd") FROM "1928_general_election" WHERE "description"='Five Cent Gasoline Tax Bill';