I just tabulated (and published) our history of bills from Xcel Energy for the last 12 months. I used google spreadsheets just to try it out and it's pretty neat. The "publish" feature makes it easy to share the thing, the I wish it would also give a "download in ODS, XLS, RTF, CSV format" link.

A couple interesting things to note:

1. We have a gas meter in our basement and Xcel checks it every year (or so) and then makes estimates based upon previous usage and current weather. So, we moved into this house 2.8 years ago. In that time they only came to read the meter once. Our usage is a bit less than the previous tenants (we use a schedule on our thermostat and don't have any kids) so this usage reflects a mix of their habits and our habits and the estimate.
2. Electricity is under a similar deal in terms of usage and estimates
3. Xcel offers a program called wind source (linked to my previous posts) that costs a little more (about $5/month for us) so our rates are a little different than most