The ranking system is calculated as a percentile - so the mailing lists are only ranked in relation to each other, rather than directly from the action taken.

The ranking system is calculated as a percentile - so the mailing lists are only ranked in relation to each other, rather than directly from the action taken. Also % of unsubscribes is only a portion of the algorithm used to calculate the overall score. The intention is not to say "this is something you should unsubscribe from because everyone else is unsubscribing from it", rather to say "based on our information, this mailing list is lower quality than most others, so you should check if you still want it"