I think the normal/average is 15-16 km/litre in city without AC. With AC roughly u can reduce 1-1.5 km/litre.
Mine Vitz in the begining gave 13-14 km/litre without AC. Then I changed driving habit with stable foot on excelrator, no hurry, no extra pushing. After that habit the average improved from 13-14 to 18+ without AC.
The next important thing is quality of petrol. Whenever, I switch to other petrol station due to some reason, average falls around 1-1.5 km/litre.
Mostly, I use PSO company operated petrol station at DHA.
However, urs average is low.