I did this back to 1935---by hand. It was pre-Pro Football Reference
It takes each category--an compares total to league leader
then divides by four, then that converted to scale of 100
I am sure it is not original, all I know is in the mid-1990s I
didn't see it online anywhere or in any books.
I did this for running backs, too, using scrimmage yards
not just rushing. I quit in 2001 . . . about hte time
PFR came online--
Went back and did a few later--but cannot find the files
anyway, I wanted something that included yards per catch
and that, in the mid-1990s was starting to be ingored as a stat
no one cared anymore so this, I thought would give it
more of an equal footing.. Mike Sando put something on Twitter
for just yards for just select guys so I dug this up===
see what you think