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:
| Driver | Constructor | Laps | Time/Retired | Grid |
| --- | --- | --- | --- | --- |
| Tony Brooks | Vanwall | 70.0 | 2:03:47.8 | 2.0 |
| Mike Hawthorn | Ferrari | 70.0 | + 24.2 | 3.0 |
| Phil Hill | Ferrari | 70.0 | + 28.3 | 7.0 |
| Masten Gregory Carroll Shelby | Maserati | 69.0 | + 1 Lap | 11.0 |
| Roy Salvadori | Cooper - Climax | 62.0 | + 8 Laps | 14.0 |
| Graham Hill | Lotus - Climax | 62.0 | + 8 Laps | 12.0 |
| Cliff Allison | Lotus - Climax | 61.0 | + 9 Laps | 16.0 |
| Maria Teresa de Filippis | Maserati | 57.0 | Engine | 21.0 |
| Giulio Cabianca | Maserati | 51.0 | Engine | 20.0 |
| Jean Behra | BRM | 42.0 | Clutch | 8.0 |
| Hans Herrmann | Maserati | 32.0 | Engine | 18.0 |
| Stuart Lewis-Evans | Vanwall | 30.0 | Overheating | 4.0 |
| Maurice Trintignant | Cooper - Climax | 24.0 | Gearbox | 13.0 |
| Stirling Moss | Vanwall | 17.0 | Gearbox | 1.0 |
| Jo Bonnier | BRM | 14.0 | Transmission | 10.0 |
| Olivier Gendebien | Ferrari | 4.0 | Suspension | 5.0 |
| Gerino Gerini | Maserati | 2.0 | Accident | 19.0 |
| Carroll Shelby | Maserati | 1.0 | Handling | 17.0 |
| Wolfgang von Trips | Ferrari | 0.0 | Accident | 6.0 |
| Harry Schell | BRM | 0.0 | Accident | 9.0 |
| Jack Brabham | Cooper - Climax | 0.0 | Suspension | 15.0 |
Question:
What was the average grid at the time Vanwall was constructor and there were 17 laps?
Answer:
1.0