CREATE TABLE table_17978 ("Member countries" TEXT, "Population" FLOAT, "Area  ( km\\u00b2 ) " FLOAT, "GDP  ( billion US$ ) " TEXT, "GDP per capita  ( US$ ) " FLOAT)

Name the gdp where gdp per capita 20200
SELECT "GDP (billion US$)" FROM table_17978 WHERE "GDP per capita (US$)" = '20200'
SELECT "GDP (billion US$)" FROM "table_17978" WHERE "GDP per capita (US$)" = '20200'