What year had an issue price of $94.95 and theme of Amethyst crystal?
CREATE TABLE "crystal_snowflake" (
  "year" real,
  "theme" text,
  "artist" text,
  "composition" text,
  "mintage" real,
  "issue_price" text
);
SELECT AVG("year") FROM "crystal_snowflake" WHERE "issue_price"='$94.95' AND "theme"='amethyst crystal';