I knew when I wrote that it was a bare assertion, based partly on memory. This is an approximation based on a few sources, the principal of which was this article, which pulls from a bunch of other sources in turn.
Those numbers aren't credible IMO because OpenRouter only see traffic for people who have chosen to route their traffic through OpenRouter. If you do that, you're much more likely to be experimenting with alternative models. They have no insight at all into people who point their applications directly at OpenAI or Anthropic without having OpenRouter in the middle.
Real question, and a refinement to my previous statement: would you find it more surprising if over 25% of worldwide inference was running on Chinese open-weight models, or not? I personally would not be shocked.
[0] https://vercel.com/blog/ai-gateway-production-index-july-202...