See stat.ML in https://tableau.cornell.edu/t/PublicContent/views/arXivSubmi...

via https://info.arxiv.org/about/reports/submission_category_by_...

So, it's not even monotonically growing.

Eh, it's a little tricky. A lot of research marketed under the "AI" umbrella would be categorized under cs.LG (https://arxiv.org/list/cs.LG/recent), cs.CV (https://arxiv.org/list/cs.CV/recent), cs.CL (https://arxiv.org/list/cs.CL/recent), and to a lesser degree cs.NE (https://arxiv.org/list/cs.NE/recent). Oh, and of course, cs.AI (https://arxiv.org/list/cs.AI/recent). Not every one of those areas has grown monotonically, but the growth in CV and CL especially has been explosive over the last ten years.

No recent data seems to be available.

https://ourworldindata.org/grapher/number-artificial-intelli...

Edit - Arxiv ML publications double every 23 months: https://twitter.com/MarioKrenn6240/status/131462299513926451...