Willyloman,
The figures for years to come will be skewed relative to years previous the the change in the 15 minute rule (pre-2003), but they will not be skewed relative to each other.
The 2.2 increase in 2003 was affected by the change,
but the "2.0" increase in 2004 was not affected by the change since the new rule was opperative in both 2003 and 2004.
The totals from now on will have benefitted from the artificial boost in 2003, but the ave increases in years to come will not be affected, since a change in policy like this can only yield short-run benefits in terms of improved growth figures.
Future changes may yeild greater artificial boosts to the numbers, but the 15 minute rule has already been spent.