Does anyone have hard numbers on what the cohorted attrition is for programmers? Ie, of the individuals employed as programmers 10 years ago, what percent are s

Does anyone have hard numbers on what the cohorted attrition is for programmers? Ie, of the individuals employed as programmers 10 years ago, what percent are still employed in programming? 20 years ago? 30 years ago? I've tried to search for this, but I think my google-fu's not up to snuff.