Firstly a 12 year old Punto may not be as economical as it was when new.
I certainly got mid 40s from mine in a variety of driving conditions.
50mpg is do-able on a poodle along a dual carriageway but don't expect that in town.
Depends on where you are driving - City, Town, Country - I would make a guesstimate that 35 m.p.g. would be a good figure for fuel economy across all the types of area that I have indicated & should be easily achievable !
N.B. Good Driving is all about anticipation - e.g. Accelerating & Braking gently if you anticipate correctly what is going to happen in front / (behind) you will 'bump up' your Fuel Economy figures tremendously !