CREATE TABLE table_48357 ("Club" TEXT, "Home city" TEXT, "Stadium" TEXT, "Founded" FLOAT, "Seasons in PRSL" TEXT)

What year was the team Club of atl tico de san juan fc who plays at hiram bithorn stadium founded.
SELECT SUM("Founded") FROM table_48357 WHERE "Stadium" = 'hiram bithorn stadium' AND "Club" = 'atlético de san juan fc'
SELECT SUM("Founded") FROM "table_48357" WHERE "Club" = 'atlético de san juan fc' AND "Stadium" = 'hiram bithorn stadium'