Every five years (years ending in 2 and 7), a comprehensive Economic Census is conducted to gather details about economic activity by sector and by state, and, in most cases, for counties and cities as well. Start with Industry and Local Business Statistics followed by Industry Snapshots for a summary for industries in the 2-digit NAICS code at the national or state level. Then click on the Industry Statistics Portal link for more details.
IBISWorld provides over a thousand research reports for trends, statistics, and analysis on market size, market share of competitors, and growth rates for both large and small industry sectors. (Rutgers-restricted access)
Case studies, industry overviews, and research reports related to many industries are available from these consulting firms:
In particular, Deloitte Insights recently provided a series of Industry Outlook reports for eight large sectors.
Frost & Sullivan offers a selection of industry reports as recorded teleconference presentations in their Analyst Briefing Archives (registration required).