I was just reading an article in the Australian Shooter on the top 10 calibres across Australia and it appears that the humble 177 caliber is the third most common in 3 of our 8 states and territories. It is also the 7th most preferred caliber in order of popularity.
The magazine only gives the 5 most common calibres in the US (see picture) so I don’t know what your top 10 are but you folks across the pond, meaning airgun enthusiasts, may need to pull your finger out. Go out and buy more 177’s.
Gary