Interesting. On the Remember the Alamo series of puzzles SW of San Antonio, the cache owner has pill bottles and 35mm film canisters listed as "Small". Geocaching.com used to use a film canister as the example for a micro cache. To me, if you can't put an normal-sized geocoin in the cache, it shouldn't be labeled as small.
To me the first chart is the most meaningful. It shows the change clearly. The chart distinguishing between caches labeled small vs micro has more issues.
The small cache designation wasn't adopted until somewhere in 2005 or later. Before that most people called them micros. My earlier data with smalls must have been people who relabeled older caches small once that designation became available. For example, people relabeled caches placed and labeled small in 2003 may have later changed them to small. My data uses when the cache was placed and I can't know if the size was changed later.
My observation is there's been size creep over time. Some new cachers are labeling caches small that in prior years would have been labeled micros. I've imagined this may partly be because newer cachers have seen so many of the tiny containers (nanos, Bison tubes, etc.), which didn't use to exist, a large pill bottle seems like it must be a small.
My intent was to show the decline of regular caches and the second chart muddies that.
I omitted 2001 & 2002 because my data's bad back then and geocaching had growing pains with some odd things going on. For what it's worth in 2001 (the first year of caching) 96% were regular caches and 4% micros in my iffy data.
I sat in on the scoring for a bit and it seemed to be going very well. We hand-checked and re-checked the scorecards so no mistakes were made. They also went out and picked up ALL the challenge caches that evening before they finished totaling the scorecards... and eliminated one of the hides from the tally because it had gone missing sometime during the competition. That said, participation was down and it appeared they had about half as many scorecards to deal with that we had last year, AND they decided ahead of time to not announce the winners until Sunday morning. That certainly took he pressure off and made things go smoother!