What is the GDP of the nation with 56,210,000 people?
CREATE TABLE "1973_enlargement" (
  "member_countries" text,
  "population" text,
  "area_km" text,
  "gdp_billion_us" text,
  "gdp_per_capita_us" text
);
SELECT "gdp_per_capita_us" FROM "1973_enlargement" WHERE "population"='56,210,000';