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:
| Rank | Diver | Preliminary\nPoints | Preliminary\nRank | Final\nPoints | Final\nRank | Final\nTotal |
| --- | --- | --- | --- | --- | --- | --- |
|  | Ingrid Krämer (EUA) | 56.30 | 1 | 34.98 | 2 | 91.28 |
|  | Paula Jean Myers-Pope (USA) | 54.70 | 2 | 35.24 | 1 | 89.94 |
|  | Ninel Krutova (URS) | 53.38 | 3 | 33.61 | 3 | 86.99 |
| 4 | Juno Stover-Irwin (USA) | 51.90 | 6 | 31.69 | 4 | 83.59 |
| 5 | Raisa Gorokhovskaya (URS) | 51.53 | 8 | 31.50 | 5 | 83.03 |
| 6 | Norma Thomas (GBR) | 51.77 | 7 | 30.44 | 7 | 82.21 |
| 7 | Nicolle Darrigrand-Pellissard (FRA) | 49.68 | 12 | 31.50 | 5 | 81.18 |
| 8 | Phyllis Long (GBR) | 52.12 | 5 | 28.86 | 9 | 80.98 |
| 9 | Irene MacDonald (CAN) | 51.31 | 9 | 29.18 | 8 | 80.49 |
| 10 | Kumiko Watanabe (JPN) | 51.04 | 10 | 28.56 | 10 | 79.60 |
| 11 | Kanoko Tsutani-Mabuchi (JPN) | 49.76 | 11 | 28.14 | 11 | 77.90 |
| 12 | Birte Christoffersen-Hanson (SWE) | 53.03 | 4 | 24.40 | 12 | 77.43 |
| 13 | Maria Teresa Adames (MEX) | 49.54 | 13 |  |  |  |
| 14 | Hanna Laursen (DEN) | 48.89 | 14 |  |  |  |
| 15 | Gabriele Schöpe (EUA) | 48.81 | 15 |  |  |  |
| 16 | Bende Velin (DEN) | 48.35 | 16 |  |  |  |
| 17 | Laura Conter (ITA) | 45.55 | 17 |  |  |  |
| 18 | Susan Knight (AUS) | 43.03 | 18 |  |  |  |
Question:
how many drivers raced in the preliminary round?
Answer:
18