Trying to nail down how many crossbow hunters there are in North America is truly a moving target.
Most states don't ask hunters to buy a specific crossbow license or permit. When hunters have to check in their harvests, few state wildlife agencies want to know specifics about what kind of archery tackle the hunters used.
Crossbow manufacturers don't publicize how many orders they are getting and filling. The Fish and Wildlife Service's national hunting survey doesn't ask about crossbows either.
However, anecdotally, there are all sorts of indicators that we're riding a tsunami of renewed interest in this ancient weapon.
Rodney Galloway, owner of a small bow shop in Statesville, N.C., said crossbows are literally "flying off the shelves."
Galloway also noted who is buying them at such a voracious rate.
"These are not bow hunters," he said. "They're rifle hunters."
Imagine if you could double your deer season by buying a new weapon.
That's what this new law means to thousands of North Carolina rifle whitetail hunters. Allowing crossbow in bow season beginning in 2010 was like adding a whole new season for these guys. And they responded.
"Talk to any rifle hunter here," Galloway said from his Strikeforce Archery store. "They are trying to expand their season."
Similar scenarios are playing out in a half dozen or so states that are allowing crossbow hunting in bow seasons.
But how many of these firearm hunters are taking up new arms across the country?
Michigan gives us another anecdotal example.
The Wolverine state made crossbow legal for all hunters in all seasons in Zone 3, which is the southern third of the state. The next year, 56,915 hunters got a free crossbow stamp. And most of the state's hunters go to Zone 2 to hunt.
The Natural Resources Commission was going to wait three years to see how the new regulation panned out. But the surge in popularity changed that: Even before the 2010 season, the NRC voted to make all but the Upper Peninsula open to crossbows during bow season and any other season.
The demand for the free crossbow stamp is expected to surge.
There are 1.2 million hunters in Michigan, and 22 percent of them are crossbow hunting, according to 2009 numbers. If the 12 million hunters in the U.S. show near as much enthusiasm as they have in Michigan, then there are 2.6 million crossbow hunters in the U.S.
"What is the true number of crossbow hunters in North America right now?" said Lee Zimmerman of the trade group North American Crossbow Federation. "I have the number. Here it is ... Growing."
"I wish I did have an accurate number," Zimmerman said. "But here's what I can say for sure: We are growing so fast, we don't even know where we are."