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:
| Game | Date | Opponent | Result | Bills points | Opponents | Bills first downs | Record |
| --- | --- | --- | --- | --- | --- | --- | --- |
| 1.0 | Sept. 16 | at New England Patriots | Win | 31.0 | 13.0 | 23.0 | 1–0 |
| 2.0 | Sept. 23 | at San Diego Chargers | Loss | 7.0 | 34.0 | 16.0 | 1–1 |
| 3.0 | Sept. 30 | New York Jets | Win | 9.0 | 7.0 | 15.0 | 2–1 |
| 4.0 | Oct. 7 | Philadelphia Eagles | Win | 27.0 | 26.0 | 16.0 | 3–1 |
| 5.0 | Oct. 14 | Baltimore Colts | Win | 31.0 | 13.0 | 18.0 | 4–1 |
| 6.0 | Oct. 21 | at Miami Dolphins | Loss | 6.0 | 27.0 | 8.0 | 4–2 |
| 7.0 | Oct. 29 | Kansas City Chiefs | Win | 23.0 | 14.0 | 21.0 | 5–2 |
| 8.0 | Nov. 4 | at New Orleans Saints | Loss | 0.0 | 13.0 | 10.0 | 5–3 |
| 9.0 | Nov. 11 | Cincinnati Bengals | Loss | 13.0 | 16.0 | 10.0 | 5–4 |
| 10.0 | Nov. 18 | Miami Dolphins | Loss | 0.0 | 17.0 | 15.0 | 5–5 |
| 11.0 | Nov. 25 | at Baltimore Colts | Win | 24.0 | 17.0 | 16.0 | 6–5 |
| 12.0 | Dec. 2 | at Atlanta Falcons | Win | 17.0 | 6.0 | 17.0 | 7–5 |
| 13.0 | Dec. 9 | New England Patriots | Win | 37.0 | 13.0 | 13.0 | 8–5 |
Question:
When is the latest game the bills had 21 first downs
Answer:
7.0