Tell me the average launced for capacity mln tpa of 15,0
CREATE TABLE "oil_refining_and_petrochemical_facilitie" (
  "name" text,
  "location" text,
  "launched" real,
  "acquired" text,
  "capacity_mln_tpa" text
);
SELECT AVG("launched") FROM "oil_refining_and_petrochemical_facilitie" WHERE "capacity_mln_tpa"='15,0';