CREATE TABLE table_204_587 (id DECIMAL, "drop ( s ) " TEXT, "multiplayer map ( s ) " TEXT, "spec ops mission ( s ) " TEXT, "face off map ( s ) " TEXT, "xbox 360 release date" TEXT, "playstation 3 release date" TEXT)

what is the total number of multiplayer maps released during this time ?
SELECT SUM("multiplayer map(s)") FROM table_204_587
SELECT SUM("multiplayer map(s)") FROM "table_204_587"