To see what other owners similar cars are doing per gallon for fuel, have a look on Honest John's Real M.P.G
site on the Daily Telegraph Website.
My 2. litre registered 2011 at 70 mph on Motorway is doing around 3500 rpm.
But fuel wise I tend to get just over 40.0 mpg on motorways.Overall average all running, town A Roads,motorways etc is showing around 35mpg. I know it's a different variation of the Mazda 2.0 litre engine
but it should give you something of a guide.Hope it helps.!