CREATE TABLE table_23999 ("Name" TEXT, "Completions" FLOAT, "Attempts" FLOAT, "Completion %" TEXT, "Yards" FLOAT, "Touchdowns" FLOAT, "Interceptions" FLOAT, "QB Rating" TEXT)

How many touchdowns were there with QB rating of 66.6?
SELECT "Touchdowns" FROM table_23999 WHERE "QB Rating" = '66.6'
SELECT "Touchdowns" FROM "table_23999" WHERE "QB Rating" = '66.6'