And with just a little more data you can actually determine how many customers you would need for each year you plan for and how many leads you would need. From that you can actually determine what size market you would need and whether your market is big enough to supply those leads that could be converted into customers.
Competitive Analysis: Business by nature is competitive, and few businesses are completely new. If there are no competitors, be careful; there may be no market for your products. Expand your concept of competition. If you plan to open the first roller skating rink in town, your competition will include movie theaters, malls, bowling alleys, etc.