I doubt this is statistically significant?
Regardless, the modern American left has become way to focused on ensuring equal odds of entering the elite (if such a thing is even possible given family connections/lack thereof) vs. improving average people's lives as they are today.
They're not using a sample; they're calculating the actual total from regulatory filings. It amounts to about sixty positions. So it does tell us something about those organizations, especially as the decrease is a break from a consistent trend.
What it doesn't provide is strong evidence for making broader inferences about how American society is changing. Which very much does not fit with either how the Washington Post covered the report or how the discussion has proceeded in this thread.
I thought that putting "12.2% to 11.8%" in the subject line would make this clear, but this thread proceeded as if I had thrown raw meat into a cage despite this. At least I learned something interesting about alewives.