http://www.exiledkingdoms.com/wiki/inde ... esistances
In fact, the resistance values can directly be interpreted as percentages only up to a value of 50. After that, a mechanism kicks in which multiplies every additional point by a penalty factor of 1/2 for values 51 to 80, 1/3 for values 81 to 110, and 1/4 for every value above 110.

Some examples for clarity:

Resistance value of 50 - Damage reduction by 50% (half damage)

Resistance value of 86 - Damage reduction by 50% + 30%/2 + 6%/3 = 67% (one-third damage)

Resistance value of 110 - Damage reduction by 50% + 30%/2 + 30%/3 = 75% (one-quarter damage)

Resistance value of 210 - Damage reduction by 50% + 30%/2 + 30%/3 + 100%/4 = 100% (immunity)