Try to measure the average in per Kg of gas instead of in terms of 1 cylinder.
I'm using honda civic VTI 2005. It normally goes app. 90 to 100 Kms in local with AC, with almost 8 Kgs of Gas. While on long it goes upto 165 with 8.6 Kgs of gas. On long the average comes to be app 19 KMs per Kg of gas. (I have measured this average more than 3 times on the motor way while travelling from Isd to Lhr).While in city the average comes to be 11 to 12 Kms per Kg of gas.
For having a better average, try to keep the air filter in neat and clean condition, dont push the accelarator to its limit specially in first two gears, try to change the plugs every 7 to 10K kilometers, though its early but its better with CNG. Keep the thermostat of your car AC a bit low and have the service of the AC done as well.
Hows your car average on petrol on long and in local??