How are you measuring this? How do you know it is paying off?
It's really not hard to save several hours of time over a month using AI tools. Even the Copilot autocomplete saves me several seconds here and there multiple times per hour.
Even when the code is not 100% correct, it's often faster to select it and make the small.fix myself than to type all of it out myself. It's surprisingly good about keeping your patterns for naming and using recent edits as context for what you are likely to do next around your cursor position, even across files.
I'm not sure it's correct that we need to measure the benefits of AI depending on the lines of codes that we wrote but on how much we ship more quality features faster.