Well something is off song or you have a thirsty driving style. Some folks think they are being "grannys" but will, for example, still hold low gears at high rpm in cruise for no good reason, or not use higher gears down gentle grades to drop the rpm, or will dance up and down on the throttle, or brake and accelerate a lot. Just check your mode of driving against others. It's all about load, piston speed, smoothness and anticipation of traffic and keeping the car rolling once it is moving.
My car is mildly worked as per my signature, I drive enthusiastically, fast but smoothly, and I hate slow dithering pests in front of me, but I run about 10.5-12 l/100 (usually around 11) in city stop start town, an easy 9.5-9.8 on local city plus freeway use, and under 9 on long trips at limit speeds plus passing blasts, and I'm not thinking consciously about fuel saving measures.
CP_e Standback & PNP; CP_e 3" SS Downpipe; Corksport FMIC with Top-mount K&N filter & OEM Ram CAI; Turbosmart BOV; Dashhawk; Prosport Boost Guage; JBR solid shift bushes; DBA 4000 Wiper-Slot front rotors; Hawk Ferro-Carbon HPS Street front brake pads (@ 69,000km); Sumitomo HTRZIII's in 225/45 x 18