How does Tier ranking work?

[satsujin]

I have films ranked in every value from 10-100 incremented by 10 each time so 10 values total but 0-40 is Tier 1 for some reason, Tier 2 is 50, there is no Tier 3, Tier 4 is 60, no Tier 5, Tier 6 is 70, no Tier 7, Tier 8 is 70, Tier 9 is 90, and Tier 10 is 100.
I would like each value on its own tier for 10,20,30,40,50,60,70.80.90,100 so how do I rank them?

[VorpalKitten]

Your bottom 10% of ratings will be Tier 1 (and top 10% will be tier 10, and so on), no matter what number you give them - so if you want the tiers to correspond exactly to 10/20/30/etc you need to rate exactly 10% of each movie you watch with each rating.