I think you'd have to start with 55+ years old and go upward to find an age range where more than 10% of programmers routinely wrote assembler code in their careers.
To find the same for machine code you'd need to start at 65 or older.
Really not the same. Assembly / machine code is entirely deterministic - they are a notation for your thoughts. LLM produced content is more a smorgasbord of other people's thoughts, and cannot help you with clarity, conviction, etc etc.
39 and have over 10 years writing assembly. huh?
change that 10% to 0.5% and I would agree. i am 62, worked in low level coding and hw interfacing. 'routinely' not even; i would say on occasion, needed to look at a bit, or even more rare, had to write a bit (like a small module)