I bet once you count 12 gauge shells in the mix theres no way. Think about how many boxes of Dove & Quail get sold each year. Hey those are centerfire.
The .22LR is by far the most used and purchased cartridge in the world.
This might be due to the fact that the .22 is a very low recoil cartridge. Moreover, almost any .22 will shoot rings around almost any rifle or pistol, bar none.
As an example:
I sent off a Springfield Armory Milspec to have it converted to a competition gun. This gun came back with the capability of achieving 1 1/2 inch groups or slightly better at 50 yards with GI ball ammo. Mind you, it took me the price of the pistol ($300.00 used), and almost $800 of work to get it to shoot that well.
On the other hand, I purchased a Ruger Competition Model, KMK-678 (6 inch barrel, slabsided, stainless). I mounted a 4x Simmons LER scope on it and took it to the range to practice and to determine which brand of .22 to use in it.
The absolutely WORST ammo I tried put ten rounds into 1 inch, sandbagged at 50 yards. The gun likes the following ammo:
1. Winchester T22, 10 rounds into 1/2 inch.
2. Federal American Eagle 40 grain solid, right at the same measurements.
3. Wolf Match Target .22, a hair above 1/2 inch, ten rounds at 50 yards.
(Note: Wolf Match Target is actually SK Jagd .22, made in Germany.)
What have I changed on that gun? I installed a Volquartsen wide trigger.
That's it. It's still box stock.
My new competition gun, which isn't a gun itself is a Marvel .22 Unit 1, mounted on a 1911 frame. This gun just flat out shoots! And, with the compensator, it is almost perfectly steady when firing. As a matter of fact, I had a sear problem with the frame it was mounted on, and the gun went full auto for 5 rounds. It was a real treat to first realize that I had fired 5 rounds--the dot did not move from the center of the target!
The second treat was to scope the target at 25 yards and see 5 clean X's.
22's are just plain fun to shoot! And, they are available in any flavor you like--from the inexpensive Ruger and the match grade IZH ar rock bottom prices, to electric-triggered free pistols costing over $3000.00 each.