ATF compiles variety of data regarding firearms in the US, and this is about the commercial sales.
Here's the link to PDF file
https://www.atf.gov/resource-center/docs/2016-firearms-commerce-united-states/download
The Firearm Blog did a nice compilation of all the data.
http://www.thefirearmblog.com/blog/2016/08/09/2016-firearms-in-commerce/
From: The Firearm Blog
