Hi Ceejay,
Your post:
"

Lee, you can get EIA historical consumption data and methodology from the link below. They have 17 years of weekly storage report data accessible from a spreadsheet (the link to that is embedded in the report).

OK, the first link under data:
History (XLS)
Gives the weekly summary injection/build data for each region, East, West, Producing and Total as of the preceeding Friday. You get the "change" by subtracting the prior weeks number.

It is this part that I do not understand:

The weekly data from year to year doesn't overlap precicely due to changes in the date of each Friday from year to year, but one can estimate fairly closely the average consumption of each week from the database within a few days. For example, the seasonal average injection for this upcoming Friday is 77.5 Bcf (19 years of data). The average 5 year injection is 77.8 Bcf. [do you mean 17 years here ??]
"
Are you saying that you are evaluating the expression that comes up in section 1 of the below link: ??
http://ir.eia.gov/ngs/methodology.html#5year

If so, can you post the chunk of the spread sheet that you are using to calculate this ??

This whole thing is not making sense to me ....

This statement also bothers me ??????
"
For example, the seasonal average injection for this upcoming Friday is 77.5 Bcf (19 years of data). The average 5 year injection is 77.8 Bcf."

Injection is the "amount supply exceeds demand" and this is saying that this has been nearly constant over a 5 year period [for those 2 numbers being approx. equal ].

Thus saying that production has been controlled/matched to demand (for the given week) for a 5 year period !!!

Am I correct in making that observation ???

If so, things are pretty well controlled. I would be sure consumption/demand has increased over the last 5 years.

Thanks, Lee