How would one go about creating a rolling HP text like Earthbound

I have 100 HP and an enemy deals a blow that causes 35 damage. I want the HP value to count down (99,98,97....65).

I want it to be similar to Earthbound's system as seen here https://youtu.be/nAmBIljqgR8?t=69 See the player "Jeff"'s HP at the 1:11 mark. I am using a plain UI Text as my HP and it is updated in my UpdateUIStats function

I tried creating a Coroutine in which I decrement the player's HP. This coroutine is called within a for loop in my DealDamage function. This loop runs as long as i is less than damageToDeal.

         for(int i = 0; i < damageToDeal; i++)
         {
             StartCoroutine(DamageCounter(target));
         }

here is my DamageCounter coroutine:

     public IEnumerator DamageCounter(int target)
     {
 
         activeBattlers[target].currentHP--;
         UpdateUIStats();
         yield return new WaitForSeconds(1f);
 
     }

 

     public void UpdateUIStats()
     {
         for(int i = 0; i < playerName.Length; i++)
         {
             if(activeBattlers.Count > i)
             {
                 if (activeBattlers[i].isPlayer)
                 {
                     BattleChar playerData = activeBattlers[i];
 
                     playerName[i].gameObject.SetActive(true);
                     playerName[i].text = playerData.charName;
                     playerHP[i].text = Mathf.Clamp(playerData.currentHP, 0, int.MaxValue) + "/" + playerData.maxHP;
                     playerMP[i].text = Mathf.Clamp(playerData.currentMP, 0, int.MaxValue) + "/" + playerData.maxMP;
                 }
                 else
                 {
                     playerName[i].gameObject.SetActive(false);
                 }
             }
             else
             {
                 playerName[i].gameObject.SetActive(false);
             }
         }
     }

The problem with this code is that it seems to have no effect, HP goes from 100 to 65. I may be way off, this is my first attempt at trying to do this. Any ideas?