user: Question: What is the average week number of all the matches where less than 22604 people attended?
Columns: ['Week', 'Date', 'Opponent', 'Result', 'Attendance']
Types: ['real', 'text', 'text', 'text', 'real']
Sample row: [1.0, 'September 27, 1953', 'at Green Bay Packers', 'W 27–0', 22604.0]
SQL:

assistant: SELECT AVG("Week") FROM "Table" WHERE "Attendance" < 22604.0;