what is the number of teams that had drivers all from the same country?
4
Team No Driver Class Chassis Engine
Carlin Motorsport 1 James Courtney C Dallara F302 Mugen-Honda
Carlin Motorsport 1 Derek Hayes C Dallara F302 Mugen-Honda
Carlin Motorsport 2 Alan van der Merwe C Dallara F302 Mugen-Honda
Carlin Motorsport 21 Michael Keohane C Dallara F302 Mugen-Honda
Carlin Motorsport 22 Shinya Hosokawa C Dallara F302 Mugen-Honda
Manor Motorsport 3 Mark Taylor C Dallara F302 Mugen-Honda
Manor Motorsport 4 Richard Antinucci C Dallara F302 Mugen-Honda
Manor Motorsport 34 Ronnie Bremer C Dallara F302 Mugen-Honda
Fortec Motorsport 5 Fabio Carbone C Dallara F302 Renault Sodemo
Fortec Motorsport 6 Heikki Kovalainen C Dallara F302 Renault Sodemo
Alan Docking Racing 7 Robbie Kerr C Dallara F302 Mugen-Honda
Alan Docking Racing 8 Mark Mayall C Dallara F302 Mugen-Honda
Alan Docking Racing 13 Tor Graves C Dallara F302 Mugen-Honda
Team Avanti 9 Matthew Gilmore C Dallara F302/Ralt F302 Mugen-Honda
Team Avanti 9 James Andanson C Ralt F302 Mugen-Honda
Team Avanti 9 Jeroen Bleekemolen C Ralt F302 Mugen-Honda
Team Avanti 10 Stefano Fabi C Dallara F302 Mugen-Honda
Promatecme UK 11 Bruce Jouanny C Dallara F302 Mugen-Honda
Promatecme UK 12 Ernani Judice C Dallara F302 Mugen-Honda
Promatecme UK 12 Matthew Gilmore C Dallara F302 Mugen-Honda
Duma Racing 14 Robert Dahlgren C Dallara F302 Mugen-Honda
Duma Racing 14 John Antoniadis C Dallara F302 Mugen-Honda
Menu Motorsport 16 Rob Austin C Dallara F302 Opel Spiess
Menu Motorsport 17 Giandomenico Brusatin C Dallara F302 Opel Spiess
Menu Motorsport 17 Stefan de Groot C Dallara F302 Opel Spiess
Motaworld Racing 18 Andrew Thompson C Dallara F302 Ford
Motaworld Racing 19 Tom Sisley C Dallara F302 Ford
Motaworld Racing 19 Stefan Hodgetts C Dallara F302 Ford
Fred Goddard Racing 51 Fairuz Fauzy S Dallara F301 Renault Sodemo
Fred Goddard Racing 52 Jason Tahinci S Dallara F301 Renault Sodemo
Fred Goddard Racing 52 Earl Goddard S Dallara F301 Renault Sodemo
Performance Racing 53 Justin Sherwood S Dallara F301 Opel Spiess
Performance Racing 54 Julien Schell S Dallara F301 Opel Spiess
Meritus Racing 55 Gavin Smith S Dallara F301 Mugen-Honda
Meritus Racing 56 Stephen Colbert S Dallara F301 Mugen-Honda
Essential Motorsport 58 Reck Junior S Dallara F301 Toyota
Essential Motorsport 58 Ricardo Teixeira S Dallara F301 Toyota
Essential Motorsport 59 Jesper Carlsen S Dallara F301 Toyota
Scuderia Etruria 60 Diego Romanini S Dallara F301 Opel Spiess
Sweeney Racing 61 Adam Carroll S Dallara F301 Mugen-Honda
Sweeney Racing 62 Billy Asaro S Dallara F301 Mugen-Honda
Sweeney Racing 63 Robert Dahlgren S Dallara F301 Mugen-Honda
Team Park 64 Stephen Colbert S Dallara F301 Opel Spiess
Team Park 64 Stefan Hodgetts S Dallara F301 Opel Spiess
Team Park 64 Adam Jones S Dallara F301 Opel Spiess
Team Park 64 David Clark S Dallara F301 Opel Spiess
Team Park 65 David Clark S Dallara F301 Opel Spiess
Diamond Racing 66 Pedro Barral S Dallara F301 Mugen-Honda
Diamond Racing 77 Harold Primat S Dallara F301 Mugen-Honda
T-Sport 67 Clivio Piccione S Dallara F301 Mugen-Honda
T-Sport 68 Karun Chandhok S Dallara F301 Mugen-Honda
Hill Speed Motorsport 69 Luke Stevens S Dallara F301 Opel Spiess
csv/204-csv/808.tsv