Not being able to resist, I wrote a quick SAS program to do correlations and regressions on these data. I also used Graph-N-Go to create two quick plots. First, we can see that for 21 years there has been a downward trend in the number of male competitors in the national championships. These data include only the regular senior divisions contested in Panamerican and Olympic competition, NOT masters divisions, visually impaired or kata. So, essentially, this is our supply of potential Olympians.
It is a pretty definite negative trend with a correlation of about -.74.
The female picture is also negative, but more complicated. Initially, there was a negative correlation of about -.48, which means the number of women has been going down also, but not as rapidly, but when you literally look at the picture, it is somewhat different.
In fact, the number of female competitors increased from 1990 to 2001 and then went into a sharp decline. Statistically, there are some really interesting (to me) ways to look at this but since this is my judo blog and not my statistics one, I will just do this.
1. Take a look at the picture from 1990 - 2001 where you can see that the overall trend was for the number of female competitors to slightly increase
2. Take a look at the picture from 2002 - 2011 whee you can see that the number of female competitors has decreased at an even faster rate than the males.
This year, there were 66 female competitors for 9 contested divisions (including 44kg and Open). In fact, only two women's divisions in the national championships (63 kg and 70 kg) had more than eight competitors.
Because I thought I remembered this but I didn't want to be one of those old people going on about how the divisions were bigger back in my day, I went into the living room and checked a picture hanging on the wall from the podium of the 1984 Senior Nationals in Los Angeles. (I have it hanging there because I was holding my one-year-old baby, Maria, in the picture and she was really adorable.)
For some reason they handed you a giant cardbook copy of the pool sheet to the first place winner. My women's division at 56 kg in 1984 was larger than most of the current men's divisions - and back then, men's divisions were regularly two to three times as large as the women's divisions. It was also about double the average size of the 57 kg division over the past decade and triple the size of the current year's division.
I'd be really interested in hearing similar statistics from other countries to know if this is just a U.S. phenomena.