I agree with Ron's post above.
In addition, the Food Standards Agency regards high fat foods as those that contain more than 20g of fat (or 5g of sat fats) per 100g, and low fat is those with under 3g/1.5g respectively per 100g. Anything in between is medium.
So, the 2% would be low fat, but the 15% would be medium but you also need to check the sat fat levels - if the fat comes from things like nuts and seeds you should still be ok (they are naturally higher in fat, but mostly the good sorts).