Not too long ago, USA Triathlon released the final standings for 2011 in which they rank all participants who have completed three or more sanctioned races of any distance. You can check out the algorithm that is used to score race performances and download rankings from 2011 back through 2005.
The top 5% earn USAT All American Honors and the next 5% earn All American Honorable Mention. (I came in at 180 in the 40-44's, putting me at 7.2%, right square in the Honorable Mention Category.)
What I found interesting was the distribution of racers across age groups, and the steady increase from 2009 to 2011. I went through the last three years of results and made a spreadsheet (yay!) of how many qualified triathletes (3 or more races) there were in each age group by gender. Below I give you the raw data and two graphs. Yes, I had other things I probably should have been doing with my time but I found this exploration irresistible!
There are nearly twice as many men as women represented. The men fall into more of a symmetrical bell curve, while participation among women seems to drop off more sharply after 44. The greatest growth area for both genders is in the 40-44, 45-49, and 50-54 age groups.
So, uh...enjoy! (Click on images to see them larger). If anyone wants the spreadsheet to play with, drop me an email and I'll send it your way.