Obviously, this will be very different from person to person, town to town, state to state, country to country. The reason why I ask, is because I've come across this graphic:
Which shows the average make up of a litre of petrol in the UK, July 2011.
When people talk about tax rates, they typically talk (when it comes to the UK) about the combination of income tax and national insurance. Other taxes that you pay after you've got your money (I don't know about other countries, in the UK, your income/NI is paid before you receive the money... can't miss what you don't have) seem to be almost ignored. But it we include employer-side taxes, VAT, duties, property tax, road tax, license fees, the average tax "rate" would be much higher.
On top of this, we see that "47.8p" goes towards the "product", which means refineries, transportation, extraction, and marketing (can't think of any other stages)... all of these also incur massive taxes. A significant portion of the "product" part of the price also, inevitably, ends up in the taxmans hands.
Finally, you also have the stealth tax of inflation.
I mean, if you add all this together, it seems that pratically ALL the wealth produced in the UK, ends up in the Government's coffers.
O/T - When you combine this with the massive Government intervention in terms of regulatory action, subsidies, etc... it's not impossible to think that market prices are so screwed up, right now, that we literally have no idea what prices would be like in a free economy. We can't possibly know if house prices are supposed to be high or low, or energy prices, or anything. Who will build the roads? Who knows, in a free society, they may never have been built... and that may have been the better alternative.
it seems that pratically ALL the wealth produced in the UK, ends up in the Government's coffers
Except it does not - they spend it faster than they get it.
On a serious side, these guys have a figure of 84%: http://www.howitends.co.uk/what-is-the-tax-burden.php. I guess you can give or take some 10%.
You can also approach this problem from the other end, and divide the total tax revenue by GDP, but I wouldn't use GDP as a reliable measure of anything.
It's not just the GDP figures I wouldn't trust, either. Governments have the incentive to under estimate both spending and tax revenues.
EDIT: Haha, you're right. The Government doesn't have coffers. Actually, it probably does. Got one built under the stimulus plan.