That's not how that works. It's highly unfeasible for someone to have gone around and ranked all 83 different Swords on an individual level, within their respective grades, and then they keep tabs on those Swords and continuously update this ranking system, that we have never once even been told about. Mihawk referred to his Sword as "The Strongest
Black Blade in the World." Although its most likely the case that a Black Supreme Grade Sword, is the actual Strongest Sword in the World, Mihawk wasn't implying that there was a ranking system within the Grades, and his was number 1.
In order for that to even be remotely possible, they'd all have to be tested extensively against each other on an individual basis, just to see how every single one performs in comparison to each other.
Even in the real World system that Oda bases this off of, there is no such individual rankings.
https://en.wikipedia.org/wiki/List_of_Wazamono