What is the GDP (billion US$) of the country that has a GDP per capita (US$) of 8,861?
CREATE TABLE "2004_enlargement" (
  "member_countries" text,
  "population" text,
  "area_km" text,
  "gdp_billion_us" text,
  "gdp_per_capita_us" text
);
SELECT "gdp_billion_us" FROM "2004_enlargement" WHERE "gdp_per_capita_us"='8,861';