There's an important distinction to make here between Wikipedia administrators -- a small, select group with special authority on the site -- and the top 1 percent of most frequent contributors, which encompasses a larger group. As Professor Chi does indeed state, the influence of administrators has declined since 2004. They are not slacking; the site at large has simply grown faster than the pool of administrators.

The bulk of edits made by the top 1 percent, on the other hand, has remained surprisingly constant since about 2003. The fifth graph in the blog post I link to in the second paragraph tells this story nicely. (Direct link below). As we see, the top 1 percent has made about half of the edits for several years. The top 5 percent has made 80 percent.

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