Which field/industry do you find the most difficult to find reports and data about it?

We are building a market research report collection platform called Hawkery.io to assist start-up founders and start-up enthusiasts in saving time and efforts to well know the market. We give away a ready-to-download report about the e-commerce industry on the website today. We are looking for your opinion to extend our resources. All of your contributions are welcomed and appreciated.