CREATE TABLE table_28973 ("No. in series" FLOAT, "No. in season" FLOAT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "Original air date" TEXT, "U.S. viewers  ( millions ) " TEXT)

How many titles have U.S. viewers 1.66 million.
SELECT COUNT("Title") FROM table_28973 WHERE "U.S. viewers (millions)" = '1.66'
SELECT COUNT("Title") FROM "table_28973" WHERE "U.S. viewers (millions)" = '1.66'