Siege attrition:

Major settlements:
lvl 1: -10%
lvl 2: -15%
lvl 3: -20%
lvl 4: -30%
lvl 5: -40%

Major settlements defences/walls/garrisons:
lvl 1: -5%
lvl 2: -15%
lvl 3: -25%

if only 2 levels:
lvl 1: -10%
lvl 2: -25%

if over 3 levels:
lvl 1: -5%
lvl 2: -15%
lvl 3: -25%
lvl 4: -40%


Minor settlements:
lvl 1: -5%
lvl 2: -15%
lvl 3: -25%

Minor settlements defences/walls/garrisons:
lvl 1: -10%
lvl 2: -25%

Nurgle factions defences/walls/garrisons/puke
All levels: -25%


Special settlements:
Praag:
lvl 1: -20%
lvl 2: -35%
lvl 3: -50%
lvl 4: -65%
lvl 5: -80%

Tor Yvresse:
lvl 1: -20%
lvl 2: -35%
lvl 3: -50%
lvl 4: -65%
lvl 5: -80%

Wei Yin:
lvl 1: -20%
lvl 2: -35%
lvl 3: -50%
lvl 4: -65%
lvl 5: -80%

Altdorf:
lvl 1: -20%
lvl 2: -35%
lvl 3: -50%
lvl 4: -65%
lvl 5: -80%

Itza:
lvl 1: -20%
lvl 2: -35%
lvl 3: -50%
lvl 4: -65%
lvl 5: -80%

Pyramid of Nagash:
lvl 1: -20%
lvl 2: -35%
lvl 3: -50%
lvl 4: -65%
lvl 5: -80%

Skavenblight:
lvl 1: -20%
lvl 2: -35%
lvl 3: -50%
lvl 4: -65%
lvl 5: -80%

Beastmen Herdstones:
lvl 1: -15%
lvl 2: -25%
lvl 3: -40%
lvl 4: -55%
lvl 5: -70%

Karak Eight Peaks:
lvl 1: -20%
lvl 2: -40%
lvl 3: -60%
lvl 4: -80%
lvl 5: -100%

Cathay bastions:
I added defensive supplies for all other variants of the bastion buildings too.
It's weird that only Cathay benefits from it.
Comparing with HEF gates and EMP forts, everyone other race gets proper defensive bonuses when owned.
lvl 1: -100% and +1000 supply
lvl 2: -100% and +1200 supply
lvl 3: -100% and +1800 supply
lvl 4: -100% and +2200 supply
lvl 5: -100% and +1500 supply

High Elf Gate bastions:
lvl 1: -100%
lvl 2: -100%
lvl 3: -100%
lvl 4: -100%
lvl 5: -100%

Empire Fort:
lvl 1: -100%
lvl 2: -100%
lvl 3: -100%
lvl 4: -100%
lvl 5: -100%


Faction bonuses:
Gor-rok:
-15% factionwide