how many drivers participated in the 8th glover trophy race?
15
col : pos | driver | entrant | constructor | time/retired | grid row 1 : 1 | innes ireland | team lotus | lotus-climax | 1.00:14.8 | 4 row 2 : 2 | stirling moss | rob walker racing team | cooper-climax | + 2.8 s | 2 row 3 : 3 | chris bristow | yeoman credit racing team | cooper-climax | + 1:05.0 s | 1 row 4 : 4 | bruce mclaren | cooper car company | cooper-climax | + 1:17.6 s | 6 row 5 : 5 | graham hill | owen racing organisation | brm | 41 laps | 9 row 6 : 6 | jo bonnier | owen racing organisation | brm | 41 laps | 10 row 7 : 7 | tony brooks | g.a. vandervell | vanwall | 41 laps | 8 row 8 : ret | roy salvadori | c.t. atkins / high efficiency motors | cooper-climax | transmission | 5 row 9 : ret | harry schell | yeoman credit racing team | cooper-climax | throttle | 3 row 10 : ret | mike taylor | taylor & crawley | lotus-climax | engine | 13 row 11 : ret | keith greene | gilby engineering | cooper-climax |  | 12 row 12 : ret | alan stacey | team lotus | lotus-climax | oil pipe | 11 row 13 : ret | dan gurney | owen racing organisation | brm | accident | 7 row 14 : wd | jack brabham | cooper car company | cooper-climax |  | - row 15 : wd | geoff richardson | geoff richardson | cooper |  | -
how many drivers participated in the 8th glover trophy race?
Pos Driver Entrant Constructor Time/Retired Grid
1 Innes Ireland Team Lotus Lotus-Climax 1.00:14.8 4
2 Stirling Moss Rob Walker Racing Team Cooper-Climax + 2.8 s 2
3 Chris Bristow Yeoman Credit Racing Team Cooper-Climax + 1:05.0 s 1
4 Bruce McLaren Cooper Car Company Cooper-Climax + 1:17.6 s 6
5 Graham Hill Owen Racing Organisation BRM 41 laps 9
6 Jo Bonnier Owen Racing Organisation BRM 41 laps 10
7 Tony Brooks G.A. Vandervell Vanwall 41 laps 8
Ret Roy Salvadori C.T. Atkins / High Efficiency Motors Cooper-Climax Transmission 5
Ret Harry Schell Yeoman Credit Racing Team Cooper-Climax Throttle 3
Ret Mike Taylor Taylor & Crawley Lotus-Climax Engine 13
Ret Keith Greene Gilby Engineering Cooper-Climax 12
Ret Alan Stacey Team Lotus Lotus-Climax Oil pipe 11
Ret Dan Gurney Owen Racing Organisation BRM Accident 7
WD Jack Brabham Cooper Car Company Cooper-Climax -
WD Geoff Richardson Geoff Richardson Cooper -
15