This March 2026 blog post is citing a 2025 study based on Sonnet 3.5 and 3.7 usage.
Given that organization who ran the study [1] has a terrifying exponential as their landing page, I think they'd prefer that it's results are interpreted as a snapshot of something moving rather than a constant.
[1] - https://metr.org/
Good catch, thanks (I really wrote that myself.) Added a note to the post acknowledging the models used were Claude 3.5 and 3.7 Sonnet.