Au total, il comprend plus de 18.000 sites et couvre approximativement 17,5% du territoire des 15 premiers États membres de l'UE (UE-15) – une superficie presque aussi grande que la France – et s'étend maintenant aux nouveaux États membres.
Altogether, it comprises over 18 000 sites and covers approximately 17.5% of the territory of the 15 initial EU Member States (EU-15) – an area almost as large as France – and is now being extended to the new Member States.