Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Week | Date | Opponent | Result | Game site | Record | Attendance |
| --- | --- | --- | --- | --- | --- | --- |
| 1.0 | September 1, 1991 | at New Orleans Saints | L 24-27 | Louisiana Superdome | 0-1 | 68,492 |
| 2.0 | September 8, 1991 | New York Jets | W 20-13 | Kingdome | 1-1 | 56,770 |
| 3.0 | September 15, 1991 | at Denver Broncos | L 10-16 | Mile High Stadium | 1-2 | 74,152 |
| 4.0 | September 22, 1991 | at Kansas City Chiefs | L 13-20 | Arrowhead Stadium | 1-3 | 71,789 |
| 5.0 | September 29, 1991 | Indianapolis Colts | W 31-3 | Kingdome | 2-3 | 56,656 |
| 6.0 | October 6, 1991 | at Cincinnati Bengals | W 13-7 | Riverfront Stadium | 3-3 | 60,010 |
| 7.0 | October 13, 1991 | Los Angeles Raiders | L 20-23 OT | Kingdome | 3-4 | 61,974 |
| 8.0 | October 20, 1991 | at Pittsburgh Steelers | W 27-7 | Three Rivers Stadium | 4-4 | 54,678 |
| 9.0 | October 27, 1991 | San Diego Chargers | W 20-9 | Kingdome | 5-4 | 58,025 |
| 10.0 | Bye | Bye | Bye | Bye | Bye | Bye |
| 11.0 | November 10, 1991 | at San Diego Chargers | L 14-17 | Jack Murphy Stadium | 5-5 | 43,597 |
| 12.0 | November 17, 1991 | at Los Angeles Raiders | L 7-31 | Los Angeles Memorial Coliseum | 5-6 | 49,317 |
| 13.0 | November 24, 1991 | Denver Broncos | W 13-10 | Kingdome | 6-6 | 60,430 |
| 14.0 | December 1, 1991 | Kansas City Chiefs | L 6-19 | Kingdome | 6-7 | 57,248 |
| 15.0 | December 8, 1991 | San Francisco 49ers | L 22-24 | Kingdome | 6-8 | 56,711 |
| 16.0 | December 15, 1991 | at Atlanta Falcons | L 13-26 | Atlanta-Fulton County Stadium | 6-9 | 53,834 |
| 17.0 | December 22, 1991 | Los Angeles Rams | W 23-9 | Kingdome | 7-9 | 51,100 |
Question:
On what date was the crowd size of 71,789?
Answer:
September 22, 1991