How to determine the value of an entire industry

[grasshopper]

I need to get an approximate value for an industry located in the U.S., what it is worth annually, to present to potential investors.
I'm not sure what keywords to use to find companies that do this sort of work. Any help would be appreciated.

If anyone knows what to call this type of research or any sites that do this, that would be awesome.

[Freelancier]

You'll end up looking at press releases for other new companies looking to get into that specific industry. The research advisory firms do the legwork, publish their guesses -- that's all it is, a guess, since the actual numbers are hidden for many firms -- and then their clients use those numbers in press releases or on their web sites. Then other people copy those numbers and re-publish them (sometimes without attribution).

What industry? Perhaps someone here already knows the answer.

[Harold Mansfield]

You have to narrow it down to something to give us a direction, however you can do this yourself easily with Google to at least get a start point.
I typed in "US Figures, Industry profits" and a whole bunch of search results came up with PDF's for different industries.