Ertiga CNG... An excellent family car..

I've driven my cng ertiga for 2500 kms till now. Wonderful, confortable and very specious car. engine performance is very good. But sometimes on highways i feel missing of 6th gear. mileage is also quite well for a car having 1.5 ltr engine. I've recieved 20 to 22 kmpl mileage on cng, depending on driving conditions. Not sure about the mileage on petrol. All in all, it's a very good family car.