Our club, the Sandusky County Regulators (Gibsonburg, OH), has seen a slight increase in monthly match attendance (we average in the upper 40's) in the past couple of years, but a significant increase (10%) at our annual 3-day match (98 vs. 88). For this year only, we decided to allow .22's. We only have one shooter that has elected to shoot .22's this year, so it didn't have a significant impact on our numbers.
I have a spreadsheet of our attendance numbers, but only back to 2015, so I can't compare any further back than then. In looking at the yearly averages since 2015, we are holding steady. We were down slightly in 2018, which I directly attribute to lousy weather. The weather forecasts were dismal for April, May, June and July, and that kept people away. Last year, we had to cancel our April and May shoots due to Covid-19. These are traditionally two month with high turnouts due to typically mild weather, so that brought our average for year down slightly.
I don't think the ammo shortage has affected us too much, although I don't hunt people down to find out why they weren't at the last match. Our local gun store has primers in stock ($10 for 100; limit 100 per day). So they're available if you want to shoot. Basically, it means your cost for primers that you'll use per match went up from $4.89 to $14.40.
Honestly, I think weather has more to do with our numbers than anything else.