I would expect inflation to run about 4% per year (Historical average).
Consistant with this, see the excerpt from the LIPA report below. Over a 5 year period, electric prices rose 4.2%/year.
From the LIPA Report 12 12 05
LIPA’s Yearly Average Price Increases
Year
Average Price
Increase
1999 to 2000 0.7%
2000 to 2001 2.3%
2001 to 2002 1.8%
2002 to 2003 5.9%
2003 to 2004 10.3%
Source: U.S. Department of Energy,
Energy Information Administration
Your data is somewhat dated. I worry about the oncoming inflation. Due to the current economics of our society (and world, for that matter), many experts are predicting double digit inflation beginning as early as 2014. Needless to say, that concerns me.