CREATE TABLE table_30151 ("No. in series" FLOAT, "No. in season" FLOAT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "Original air date" TEXT, "Production" TEXT, "U.S. viewers  ( in millions ) " TEXT)

How many viewers in millions were there for episode 4 of this season?
SELECT COUNT("U.S. viewers (in millions)") FROM table_30151 WHERE "No. in season" = '4'
SELECT COUNT("U.S. viewers (in millions)") FROM "table_30151" WHERE "No. in season" = '4'