Table:
text: 2008 Indianapolis motorcycle Grand Prix
125cc classification
125cc classification
Rider Manufacturer Laps Time_ Grid
Nicolas Terol Aprilia 16 29:51.350 6
Pol Espargaro Derbi 16 +1.708 1
Stefan Bradl Aprilia 16 +3.984 3
Scott Redding Aprilia 16 +4.277 9
Sandro Cortese Aprilia 16 +4.413 10
Marc Marquez KTM 16 +4.454 13
Simone Corsi Aprilia 16 +6.261 7
Bradley Smith Aprilia 16 +7.782 11
Steve Bonsey Aprilia 16 +12.035 15
Mike Di Meglio Derbi 16 +12.251 2
Dominique Aegerter Derbi 16 +15.465 8
Joan Olivé Derbi 16 +18.312 12
Raffaele De Rosa KTM 16 +20.137 17
Gabor Talmacsi Aprilia 16 +24.651 16
Danny Webb Aprilia 16 +27.592 4
Jules Cluzel Loncin 16 +35.432 31

text: 2008 Indianapolis motorcycle Grand Prix
125cc classification
125cc classification
Rider Manufacturer Laps Time_ Grid
Robin Lasser Aprilia 16 +37.082 22
Sergio Gadea Aprilia 16 +38.549 23
Tomoyoshi Koyama KTM 16 +38.571 18
Efren Vazquez Aprilia 16 +40.991 24
Hugo Van Den Berg Aprilia 16 +1:06.197 30
PJ Jacobsen Aprilia 16 +1:06.327 25
Bastien Chesaux Aprilia 16 +1:07.067 34
Jonas Folger Aprilia 16 +1:14.709 29
Robert Muresan Aprilia 16 +1:20.413 32
Alexis Masbou Loncin 16 +1:21.880 27
Davide Stirpe KTM 16 +1:22.026 33
Cyril Carrillo Honda 16 +1:22.159 35
Kristian Lee Turner Aprilia 16 +2:11.524 36
Lorenzo Zanetti KTM 13 Retirement 28
Marco Ravaioli Aprilia 10 Accident 26
Pablo Nieto KTM 9 Retirement 20
Michael Ranseder Aprilia 7 Accident 19

text: 2008 Indianapolis motorcycle Grand Prix
125cc classification
125cc classification
Rider Manufacturer Laps Time_ Grid
Takaaki Nakagami Aprilia 6 Accident 14
Andrea Iannone Aprilia 5 Retirement 5
Esteve Rabat KTM 2 Accident 21

Question: What is the average starting grid for vehicles manufactured by Aprilia that have completed more than 16 laps in the 125cc classification of the 2008 Indianapolis Motorcycle Grand Prix?