They have three sets of weights to adjust the scores across nine different metrics. Here is their 2021 version which did the same but let you alter the weights yourself (would be nice if they'd still offered it this year, but they had their reasons not to):

https://spectrum.ieee.org/top-programming-languages/

You can see the likely weights they used for the three rankings they show this year.

As to what it means 100 vs 70.22 means, it means that Python got a higher score under that ranking. It showed up in more places.