CREATE TABLE table_33372 ("Year" FLOAT, "Network" TEXT, "Play-by-play" TEXT, "Color commentator ( s ) " TEXT, "Sideline reporter ( s ) " TEXT)

For how many years combined were Frank Gifford and Dan Dierdorf color commentators?
SELECT COUNT("Year") FROM table_33372 WHERE "Color commentator(s)" = 'frank gifford and dan dierdorf'
SELECT COUNT("Year") FROM "table_33372" WHERE "Color commentator(s)" = 'frank gifford and dan dierdorf'