If you graph this data, you find that for the time period above, Ruger produced about 1/10 as many firearms as there were NICS checks, which implies that Ruger has about a 10% market share of firearms sold in the U.S., and also there is a simple relation between NICS checks (adjusted) and firearm sales. Roughly speaking, this is consistent with the fact that Ruger has a 14% share of pistol production by U.S. manufacturers, and roughly 1/4 of weapons sold in the U.S. are foreign imports.
Anyway, I estimate you can make a guess about Ruger units produced in any time period by multiplying the Adj. NICS checks by 10%.
If Ruger revenues grow faster than NICS checks, it may be the result of price increases, richer mix of product sold, or gains in market share.
I calculated previously for 2011 (most recent data available) that Ruger had 23.1%, 33.9%, and 25.0% market share of American Manufacturers for Pistols, Revolvers, and Handguns, respectively, based on production (not sales).
For 2011 Long Guns it was 10.1% market share of production by American Manufacturers.
For all firearms in 2011, it was 17.0% market share, again just of production (not sales) by American Manufacturers.
I didn't know that 25% of sales were imports, that's interesting to know. I guess, multiply the above figures by .75 to make it for all sales (domestic mfgs and imports).
Where do you get the 14% market share sales of US mfgs. figure for pistols? Did you mean all mfgs? (That'd be more like 18.8% though, from my data combined with your 25% imports figure).
For all firearms for 2011, for all mfgs (domestic and import) I guess it'd be 17% x 0.75 = 12.8%
In 2011, there were 5.5 million US manufactured firearms, and 3.2 million imports, and 10.8 million adjusted NICS, according to ATF data. That suggests imports were about 3.2/10.8=30% of all firearms sold---I assume some of the NICS checks were for used weapons, which is why the total NICS checks doesn't match the US and import totals. Distributors shipped about 1.09 million Ruger units in 2011, according to the 10-K. That suggests Ruger share of weapons was about 1.09/10.8=10% in 2011.