CREATE TABLE table_67542 ("Member countries" TEXT, "Population" TEXT, "Area  ( km\\u00b2 ) " TEXT, "GDP  ( billion US$ ) " TEXT, "GDP per capita  ( US$ ) " TEXT)

What is the per-capita GDP for the country with an overall GDP of 156.640?
SELECT "GDP per capita (US$)" FROM table_67542 WHERE "GDP (billion US$)" = '156.640'
SELECT "GDP per capita (US$)" FROM "table_67542" WHERE "GDP (billion US$)" = '156.640'