Below is a scenario with 3 questions, which I've already answered. The question I need help answering is the "Critical Thinking" question at the bottom.

Scenario: You have created a new app for the iPhone, which allows users to locate trained, experienced babysitters within a specific zip code in the U.S. You would like to market the app through Apple's App Store, but need to develop an estimate of potential users who might purchase it. You have determined that iPhone users tend to have above-average annual household income ($75,000+), and be more likely to have completed a 4-year college degree. Using the websites listed above, answer the following questions for 2012 (the most recent American Community Survey data released):

1. How many family households in the U.S. had children under age 12?
48,552 family households in the U.S. had children under age 12.

2. How many family households in the U.S. were headed by an individual who had completed a bachelor's degree?
23,782 U.S. family households were headed by an individual who had completed a bachelor's degree.

3. How many U.S. families had an average annual household income of $75,000 or more?
34,263 U.S. families had an average annual incomve of $75,000 or more.

Critical Thinking Question

What other market data would you need to create an accurate sales forecast for the babysitter app?