Why agents do not write most of our code – a reality check

> We have good reasons for not jumping on the bandwagon of companies like Anthropic (generating 80%), Microsoft (30%) or Google (25%) just yet.

How do they measure that? I'd like to know how much I've been using coding agents to code versus by me but haven't found any reliable way to track which part of the code was from AI agents and which was from me.