CREATE TABLE table_30628 ("No. in series" FLOAT, "No. in season" FLOAT, "Title" CLOB, "Directed by" CLOB, "Written by" CLOB, "Original air date" CLOB, "Prod. No." FLOAT, "Viewers  ( millions ) " CLOB)

How many seasons had 16.15 million viewers?
SELECT COUNT("No. in series") FROM table_30628 WHERE "Viewers (millions)" = '16.15'
SELECT COUNT("No. in series") FROM "table_30628" WHERE "Viewers (millions)" = '16.15'