If you mean, "is it reasonable that it has not changed for such a length of time?" then the answer is yes. For all we moan about petrol prices, they have been fairly static overall and cars are more efficient and reliable than ever before. As Alisonjoy says, what is more important is that you know how to claim the difference back from the taxman, as the amount your company pays you is only part of what you get out of such claims.