I dont know if some one will believe my Daewoo Racer Figures But these are real
CNG ( 55- Cyl)
Within Islamabad with AC = 120-130 KMs
Within Islamabad without AC = 130-145 KMs
Highway ( 80-100 KM/Hr) = 200-210 KMs
Highway ( 100-120 KM/Hr) = 170-185 KMs
Highway (120-150 KM/Hr) = 140-150 KMs
For calculating Petrol averages you need to fill up the whole tank and then take averages on next fill up. So I have only done this a few times.
Within City = 10 KM / Litter
Highway = 12-14 KM per litter depending on drive style.
My best average on petrol on motorway ( speed never crossed 100) while I drove from Faisalabad to Islamabad was 15 KM per litter which was amazing.