DC Barrel Connecor size documented?

Is the size of the DC barrel connector documented anywhere?
The two popular sizes these days seem to be 2.1mm and 2.5mm.
I believe that is the diameter of the inside pin.
I believe the OD of the outside barrel is 5mm (?)
I also assume that the size of that connector has been the same for all the generations?

The same specification on all generations of genuine Unos