If I get a chance, I’ll make the lines easier to follow, but this is a list of the proportion of divisional bouts (using our limits — men only) taking place within a calendar year. In other words, 27.6% of bouts in 2001 that we have division info for, took place at Heavyweight.
Here is a summary data chart for the presented data:
| Fly | Bantam | Feather | Light | Welter | Middle | LtHeavy | Heavy | |
| Avg | 2.4% | 5.1% | 10.4% | 19.2% | 17.3% | 15.7% | 11.3% | 18.5% |
| 2001 | 1.1% | 4.7% | 6.9% | 12.7% | 15.2% | 14.4% | 17.4% | 27.6% |
| 2011 | 3.0% | 8.6% | 13.6% | 23.3% | 19.6% | 14.5% | 9.2% | 8.2% |
| Diff | 2.7x | 1.8x | 2.0x | 1.8x | 1.3x | 1.0x | 0.5x | 0.3x |
I suppose this data could be somewhat influenced by my data mining and availability. After all, it was much easier to assume that Dan Severn fought an indie bout in 2001 at Heavyweight than to figure out if Matt Hughes fought at Welter or Middle, at a random Extreme Challenge event.
That aside, the trends don’t lie. The proportions of Light Heavyweight and Heavyweight have taken drastic drops since 2001 in the amount of bouts that have taken place at those divisions. Middleweight has stayed pretty constant throughout, while the lighter divisions have seen a huge increase in bouts. Check out Flyweight, with a proportion increase of almost 3 times!