Trade associations collect information on their industry. IBISWorld will list relevant associations on the first page of the report under "Additional Resources." Sometimes they will provide free data, but other times you may have to contact the association directly to see what they have. Check out the website and look for links labeled "Research," "Media," or "Statistics."
Trade journals can provide valuable data for the entrepreneur. Trade associations often publish them and may provide access via their website. You'll also find trade magazines listed in the "Industry References" section of Industry Surveys (NetAdvantage).