This was at 100km/h. This 24 km include city drive from DHA3 to ring road and then cruise at 100km/h. If u constant keep ur car at 70 or 80. Im sure city will show 20 plus average 
BTW actually average is tank to tank. U may keep ur fuel average at 20 for certain trip, but at the end of the day, with stop and go traffic, and city drive u wont get better than 14.
Im getting 11.5 to 12 for city drive at peak rush hours if i calculate on 400km plus drive.