Does anyone know of a formula from which to determine the size of a local market? I'm considering opening a small brewery in a midwest town and need to determine the size of the market without spending huge sums of money on market research companies. I've started by emailing the investor relations dept's of several public companies about their beer sales in individual restaurants. I'm also able to determine how many restaurants are in the area by using switchboard.com. Any suggestions on the best approach? Thanks.

Richard