CREATE TABLE table_24138 ("Rank" FLOAT, "Commodity" TEXT, "Value  ( Int $1000 ) " FLOAT, "Production  ( MT ) " FLOAT, "Quantity world rank" TEXT, "Value world rank" TEXT)

When the value world rank is 7, what is the rank?
SELECT "Rank" FROM table_24138 WHERE "Value world rank" = '7'
SELECT "Rank" FROM "table_24138" WHERE "Value world rank" = '7'