Unfortuneatly everyone has different situations, ages, locations so it varies
The only true qoute which would be accurate and of benfit for yourself would be to find someone of same age, location and situation and on the forum but unfortuneatly that is nigh on impossible
as said it isnt just a figure for everyone at the same age
insurance works on a 'base rate' which means insurance is affected by different factors which move the base rate.
These include things like
age
gender
convictions
claims
no claims bonus
addres where car to be kept
where car is kept (although this is only on certain cars i.e. requirement for some postcodes with some cars have to be kept in a garage overnight)
pass plus
named drivers
modifications
occupation
type of use
cover required i.e. (third party only, third party fire and theft)
additional benefits such as motor legal protection,temporary replacement car
Best plan is to ring around and shop about, dont just go for the cheapest as if you are to claim then you could find that the premium you paid does not cover basic things you need when it comes to claiming
i considered the GP because of the low insurance group (6) for it's power, but it isn't fully down to the insurance group as i found out yesterday, nobody would quote me on a GP a while back.