Here's a list of FC contributed by drivers of various car makes.
Have a look.
My car forum fuel consumption list
Picanto isn't meant to be a car to be driven hard, unless you are
thinking about filter left with over a hundred km/h, you usually
don't have to think about its stability. At high speed, its heavy
kerb does provide some sense of security, much better than mine
(kelisa). And it 100cc bigger engine allows you to push the little
Pi even faster.
Low cost, low maintence, good FC, point A to B, how about Kelisa?
Actually Aveo(M)
should be within your range too. With some discipline driving, it
can do 14km/L FC figure. Or the Siron, going at around 50k now, I
would consider it being among 1 of the better cars. FC is good at
17km/L.
Lastly, if your main concern is FC, then you shouldn't be thinking
about auto-transmission cars. Unless you don't have the appropriate
license. Difference between Auto and manual car of the same make
can be as much as 3km/L.
Don't let a moment of
weakness cause you 10 years of regret.