Actually I can tell you exactly the number of first time buyers I had. So much for your assumption.
...but I noticed you didn't, not that it matters. If you know how many first timers you have had, then you must also know how many total buyers you have had and total purchases you have had.
Maybe YOU can tell us, but you are a small operation and you don't sell many guns, not compared to the Walmarts, Ganders, Cabelas, Academys, Bud's, and other such stores that have lots of customers, lots of employees, and who don't keep such records. Sure, any employee can spot a person they think or are told is a first timer, but that doesn't translate into real data.
Given the millions of sales that we are talking about here, I am fairly certain the GSSF didn't survey the thousands of small FFLs to get their data or bother to verify that the FFLs they did survey could actually show real data to support the numbers reported. Were you and Miss Stana surveyed? The two local FFLs I deal with were not. One of my tenants who is an FFL was not. Hmmm.
Miss Stana has a small shop as she noted and can tell who is a new customer. However, I noticed she didn't claim to not the exact number of new buyers she has had.