"50 Years After" Enemy Rankings

Introduction
In my upcoming game 50 Year After, there will be an enemy ranking system where enemies will have their stats ranked by the letters A, B, C, and D. Speed/Walk speed, health, and damage are what will be ranked.

Rankings

Damage

A = 20-25 Damage will be dealt.
B = 16-18 Damage will be dealt.
C = 13-15 Damage will be dealt.
D = 5-10 Damage will be dealt.

Speed/Walk Speed

A = 20-25 Walk Speed
B = 17-18 Walk Speed
C = 16 Walk Speed
D = 5-10 Walk Speed

Health

A = 80-100 HP
B = 70-75 HP
C = 30-50 HP
D = 15-25 HP