user: Question: How many seasons had 16.15 million viewers?
Columns: ['No. in series', 'No. in season', 'Title', 'Directed by', 'Written by', 'Original air date', 'Prod. No.', 'Viewers (millions)']
Types: ['real', 'real', 'text', 'text', 'text', 'text', 'real', 'text']
Sample row: [25.0, 1.0, '"Human Traffic"', 'James Whitmore, Jr.', 'Shane Brennan', 'September21,2010', 201.0, '15.76']
SQL:

assistant: SELECT COUNT("No. in series") FROM "Table" WHERE "Viewers (millions)" = '16.15';