Calling Different numbers one after another

Hello, okay so what im trying to do is make a attack code that will randomize attack points(Attack points = how much life is lost) from what i gathered and already tried i using the Random.Range,, that just takes random numbers off i didn't want this i wanted something such as when the first hit is like -10 life, then the next -5 life, and so on, i was thinking of an array of numbers been called one after each other giving the effect of random life loss, without it actually been random, basicly so i have control of how much (LifePoints) i lose, i wouldn't know where to start, here is the code im using,

 using UnityEngine;

using System.Collections;

public class Enemyattack : MonoBehaviour { public GameObject target; public float attackTimer; public float coolDown;

 // Use this for initialization
 void Start () 
 {
     attackTimer = 0;
     coolDown = 2.0f;
 }
 
 // Update is called once per frame
 void Update () 
 {
     if(attackTimer > 0)
         attackTimer -= Time.deltaTime;
     
     if(attackTimer < 0)
         attackTimer = 0;
     
     if(attackTimer ==0){
         Attack();
         attackTimer = coolDown;
     }
 }
 
 private void Attack(){
     float distance = Vector3.Distance(target.transform.position, transform.position);
     
     Vector3 dir = (target.transform.position - transform.position).normalized;
     
     float direction = Vector3.Dot(dir, transform.forward);
     
     if(distance < 4){
         if(direction > 0){
     Health eh = (Health)target.GetComponent("Health");
     eh.AddjustCurrentHealth(-10);
         }
     }

 }

}

If anyone could help please feel free to :)

Thanks