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:
| Rider | Manufacturer | Laps | Time/Retired | Grid |
| --- | --- | --- | --- | --- |
| Arnaud Vincent | Aprilia | 18.0 | +46:22.971 | 2.0 |
| Mirko Giansanti | Honda | 18.0 | +1.164 | 15.0 |
| Manuel Poggiali | Gilera | 18.0 | +2.558 | 5.0 |
| Noboru Ueda | Honda | 18.0 | +3.479 | 18.0 |
| Simone Sanna | Aprilia | 18.0 | +10.188 | 19.0 |
| Shuhei Aoyama | Honda | 18.0 | +23.056 | 12.0 |
| Ángel Rodríguez | Aprilia | 18.0 | +23.653 | 13.0 |
| Dani Pedrosa | Honda | 18.0 | +33.488 | 1.0 |
| Lucio Cecchinello | Aprilia | 18.0 | +34.285 | 3.0 |
| Gino Borsoi | Aprilia | 18.0 | +47.304 | 11.0 |
| Stefano Perugini | Italjet | 18.0 | +1:01.770 | 24.0 |
| Klaus Nöhles | Honda | 18.0 | +1:06.064 | 14.0 |
| Joan Olivé | Honda | 18.0 | +1:28.936 | 25.0 |
| Alex Baldolini | Aprilia | 18.0 | +1:36.264 | 29.0 |
| Steve Jenkner | Aprilia | 18.0 | +1:56.859 | 7.0 |
| Héctor Barberá | Aprilia | 18.0 | +2:11.594 | 33.0 |
| Mattia Angeloni | Gilera | 18.0 | +2:14.164 | 37.0 |
| Imre Tóth | Honda | 18.0 | +2:17.104 | 36.0 |
| Sunathai Chaemsap | Honda | 18.0 | +2:35.641 | 23.0 |
| Stefano Bianco | Aprilia | 15.0 | Accident | 20.0 |
| Toshihisa Kuzuhara | Honda | 14.0 | Accident | 22.0 |
| Jakub Smrž | Honda | 13.0 | Accident | 26.0 |
| Youichi Ui | Derbi | 12.0 | Accident | 10.0 |
| Chaz Davies | Aprilia | 12.0 | Accident | 27.0 |
| Jaroslav Huleš | Aprilia | 7.0 | Accident | 4.0 |
| Andrea Ballerini | Honda | 7.0 | Accident | 30.0 |
| Mika Kallio | Honda | 7.0 | Accident | 31.0 |
| Masao Azuma | Honda | 6.0 | Accident | 6.0 |
| Andrea Dovizioso | Honda | 6.0 | Accident | 28.0 |
| Gábor Talmácsi | Italjet | 5.0 | Retirement | 21.0 |
| Michel Fabrizio | Gilera | 5.0 | Retirement | 35.0 |
| Jarno Müller | Honda | 5.0 | Accident | 16.0 |
| Hideyuki Ogata | Honda | 4.0 | Accident | 32.0 |
| Pablo Nieto | Aprilia | 3.0 | Accident | 17.0 |
| Alex de Angelis | Aprilia | 1.0 | Accident | 8.0 |
| Max Sabbatani | Aprilia | 0.0 | Accident | 9.0 |
| Akira Komuro | Honda | 0.0 | Accident | 34.0 |
Question:
What is the average number of laps with an accident time/retired, aprilia manufacturer and a grid of 27?
Answer:
12.0