According to the law of diminishing marginal returns

the u.s. census bureau produces data on the population and economy nationwide. it can you to analyze the kind of people living in your neighborhood. it does not show you the market of people willing to buy your product or an existing market for your product. that will require more market research. the census bureau only gives you an insight to the demographics in your area.

answer; niosh, the national institute for occupational safety and health;

answer; at prices that violate government price regulations;