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 |
| --- | --- | --- | --- | --- |
| Sergio Gadea | Aprilia | 18.0 | 38:09.44 | 8.0 |
| Joan Olive | Derbi | 18.0 | +0.932 | 9.0 |
| Stefan Bradl | Aprilia | 18.0 | +1.660 | 15.0 |
| Mike di Meglio | Derbi | 18.0 | +1.771 | 3.0 |
| Scott Redding | Aprilia | 18.0 | +1.819 | 4.0 |
| Danny Webb | Aprilia | 18.0 | +7.689 | 5.0 |
| Simone Corsi | Aprilia | 18.0 | +8.684 | 10.0 |
| Pol Espargaró | Derbi | 18.0 | +8.693 | 18.0 |
| Efren Vazquez | Aprilia | 18.0 | +9.054 | 19.0 |
| Nicolás Terol | Aprilia | 18.0 | +10.902 | 7.0 |
| Sandro Cortese | Aprilia | 18.0 | +10.945 | 13.0 |
| Gábor Talmácsi | Aprilia | 18.0 | +12.618 | 2.0 |
| Stefano Bianco | Aprilia | 18.0 | +12.709 | 12.0 |
| Andrea Iannone | Aprilia | 18.0 | +20.086 | 17.0 |
| Michael Ranseder | Aprilia | 18.0 | +23.575 | 22.0 |
| Bradley Smith | Aprilia | 18.0 | +23.890 | 1.0 |
| Dominique Aegerter | Derbi | 18.0 | +29.406 | 20.0 |
| Pablo Nieto | KTM | 18.0 | +32.891 | 16.0 |
| Takaaki Nakagami | Aprilia | 18.0 | +33.346 | 23.0 |
| Pere Tutusaus | Aprilia | 18.0 | +33.649 | 26.0 |
| Lorenzo Zanetti | KTM | 18.0 | +36.696 | 24.0 |
| Randy Krummenacher | KTM | 18.0 | +36.754 | 25.0 |
| Robin Lasser | Aprilia | 18.0 | +45.317 | 27.0 |
| Esteve Rabat | KTM | 18.0 | +56.440 | 11.0 |
| Louis Rossi | Honda | 18.0 | +1:14.502 | 34.0 |
| Raffaele de Rosa | KTM | 15.0 | Accident | 6.0 |
| Dino Lombardi | Aprilia | 11.0 | Mechanical | 32.0 |
| Hugo van den Berg | Aprilia | 10.0 | Accident | 29.0 |
| Tomoyoshi Koyama | KTM | 8.0 | Accident | 21.0 |
| Stevie Bonsey | Aprilia | 5.0 | Accident | 14.0 |
| Jules Cluzel | Loncin | 4.0 | Accident | 30.0 |
| Alexis Masbou | Loncin | 1.0 | Mechanical | 28.0 |
| Roberto Lacalendola | Aprilia | 1.0 | Mechanical | 33.0 |
| Robert Muresan | Aprilia | 0.0 | Mechanical | 31.0 |
Question:
What was the highest grid value for riders with manufacturer of Aprilia and time of +1.660?
Answer:
15.0