How many mile to the gallon does a 1994 vaxhall corsa 1.4liter do?

Hi, I have a 1998 r reg Tigra 1.4. I can fill her with £30 and get 270 miles, which works out at about 45 miles per gallonwhen i drive casually and changing gear at no more than 2,500rpm. My email is brianb130486@hotmail.com if you would like any other info. Brian