user: Question: What is the average number of weeks that the opponent was the Denver Broncos?
Columns: ['Week', 'Date', 'Opponent', 'Result', 'Kickoff Time', 'Attendance']
Types: ['real', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, 'September 7, 2003', 'Denver Broncos', 'L 30–10', 'CBS 1:00pm', '63,820']
SQL:

assistant: SELECT AVG("Week") FROM "Table" WHERE "Opponent" = 'Denver Broncos';