a Coal Index

I've been looking for an Index which covers coal stocks and ...

>Because you invest in coal stocks, right?
Well, yes ... but it'd be neat to be able to create my own index which covers, say, gold stocks or car companies or retail stores etc. etc.
So I figured I could download a gaggle of stock prices, weight them according to market caps and generate an index.

>Like the DOW.
No, the DOW is proportional to the average price of 30 stocks. Bigger stock prices have more weight.
It'd be more like the S&P where bigger companies (measured by the total value of all stocks) have more weight.

The spreadsheet looks like this (where you can click on the picture to download it):

You type in a dozen (Yahoo) stock symbols and some benchmark (like the DOW), then click a button.
I picked a dozen which have mkt caps over (about) $1B. In fact, them "weights" are the mkt caps, in billions - BTU being the largest.
A years's worth of prices are downloaded and plotted and an Index is calculated based upon the dozen market capitalizations.

>And I type in a dozen market caps? You kidding?
Uh ... no. There's a separate sheet that'll do that. It downloads the market caps and generates the various weights. It looks like this:

>I'm looking at the picture of the spreadsheet. Judging from the coal index chart, compared to the DOW, coal stocks don't look good.
That's over the past year, but check out the past six months:
Looks good, eh?

>The past six months? Can I ask for that ... in the spreadsheet?
Don't tell nobody, but cell B2 says:   =B3 - 365   (that's going back a year, eh?)
But, if'n you're careful, you can change it to   =B3 - 365/2   (that's a half-year, eh?)

>I assume your coal stocks is doin' good.
You mean GCE and WTN? So far, so good.

Note, however, that you can change the "Title" from COAL INDEX to, say,
CAR INDEX and type in a dozen car company symbols.
Or, maybe, GOLD INDEX where you stick in your favourite Gold companies.
Or, maybe, SHIPPING INDEX where you stick in your favourite Shipping companies, like:

>But that ain't a dozen shipping stocks.
That's okay. Try it.