How do i add coins in my Save Total Coin, everytime i collect more coins in the game?

I have a Save "Total Coin" and I want the add coins in the Save "Total Coin" every time I collect some in the game. My Save and load scripts, right here:

 public class ScoreManager : MonoBehaviour {
  
  public int CoinCount;
     
 
   public void Save()
     {
         BinaryFormatter BF = new BinaryFormatter();
         FileStream file = File.Create(Application.persistentDataPath + "/PlayerInfo.dat");
 
         PlayerData data = new PlayerData();
         data.coinCount = CoinCount;
         data.Highscore = HiScoreCount;
         BF.Serialize(file, data);
         file.Close();
     }
 
     public void load()
     {
         if (File.Exists(Application.persistentDataPath + "/PlayerInfo.dat"))
 
         {
             BinaryFormatter BF = new BinaryFormatter();
             FileStream file = File.Open(Application.persistentDataPath + "/PLayerInfo.dat", FileMode.Open);
             PlayerData data = (PlayerData)BF.Deserialize(file);
             file.Close();
             CoinCount = data.coinCount;
             HiScoreCount = data.Highscore;
 
 
         }
     }
 }
 
 [Serializable]
 class PlayerData
 {
     public int coinCount;
     public float Highscore;
 }

I collect the coins with this script:

  void OnTriggerEnter2D(Collider2D other)
     {
         if (other.CompareTag("coins"))
         {
             ScoreManager.GetInstance().CoinCount += 1;
             other.gameObject.SetActive(false);
         
             
         }
 
     }

I am stuck and cannot find any solutions. Some help please.