What is the range of CNG vehicles?

What is the range of CNG vehicles?

The total capacity (in litres) of cylinders installed divided by four gives with good approximation the equivalent CNG cubic metres contained into the tank.
For example, a 80 litres cylinder contains about 20 cubic meters of CNG.
Assuming to average 14 km to the CNG cubic metre (roughly equivalent to 12,5 km per petrol litre), the range should be at around 280 km.