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:
| Pos | No | Driver | Constructor | Laps | Time/Retired | Grid |
| --- | --- | --- | --- | --- | --- | --- |
| 1 | 12 | Clay Regazzoni | Ferrari | 60 | 1:01:25.34 | 3 |
| 2 | 4 | Patrick Depailler | Tyrrell-Ford | 60 | + 0:08.35 | 5 |
| 3 | 2 | Jochen Mass | McLaren-Ford | 60 | + 0:15.44 | 4 |
| 4 | 5 | Ronnie Peterson | Lotus-Ford | 60 | + 0:40.14 | 10 |
| 5 | 18 | John Watson | Surtees-Ford | 60 | + 0:45.55 | 6 |
| 6 | 8 | Carlos Pace | Brabham-Ford | 60 | + 0:45.90 | 7 |
| 7 | 16 | Tom Pryce | Shadow-Ford | 60 | + 0:46.66 | 8 |
| 8 | 24 | James Hunt | Hesketh-Ford | 59 | + 1 Lap | 11 |
| 9 | 31 | Chris Amon | Ensign-Ford | 59 | + 1 Lap | 9 |
| 10 | 21 | Jacques Laffite | Williams-Ford | 59 | + 1 Lap | 13 |
| 11 | 9 | Vittorio Brambilla | March-Ford | 58 | + 2 Laps | 12 |
| 12 | 22 | Rolf Stommelen | Hill-Ford | 58 | + 2 Laps | 14 |
| 13 | 35 | Tony Trimmer | Maki-Ford | 54 | + 6 Laps | 16 |
| NC | 20 | Jo Vonlanthen | Williams-Ford | 51 | + 9 Laps | 15 |
| Ret | 17 | Jean-Pierre Jarier | Shadow-Ford | 33 | Transmission | 1 |
| Ret | 1 | Emerson Fittipaldi | McLaren-Ford | 6 | Clutch | 2 |
Question:
how many drivers participated in the race?
Answer:
16