List of Class With GameObject

Hello, Unity Community.

I'm trying to make a dynamic table as shown on Fig.1.

  using UnityEngine;
  using System.Collections;
  using UnityEngine.UI;
  using System.Collections.Generic;
  
  //List Of Class NPC(GameObject, x, y, z, p, Hi, Hc)
  public class NPC : MonoBehaviour {
  
  public GUIStyle customGuiStyle;
  public RandomPressure _RandomPressure;
  public Label1 _Label1;
  private GameObject GONPC;
  private int i;
  private int s1;
  private string s;
  private float xnpc;
  private float ynpc;
  private float znpc;
  private float pplayer;
  private float Hinitial;
  private float Hcurrent;
  private List<NPC> NPCList = new List<NPC>();
  public NPC(GameObject GONPC1, float xnpc1, float ynpc1, float znpc1, float pplayer1, float Hinitial1, float Hcurrent1)
  {
  GONPC1 = GameObject.FindGameObjectWithTag("NPC");
  GONPC = GONPC1;
  xnpc = xnpc1;
  ynpc = ynpc1;
  znpc = znpc1;
  pplayer = pplayer1;
  Hinitial = Hinitial1;
  Hcurrent = Hcurrent1;
  }
  void Start()
  {
  Hinitial = 100;
  }
  void Update() 
  {
  NPCList = new List<NPC>();
  for (i = 0; i == NPCList.Count; i++)
  {
  GONPC = GameObject.FindGameObjectWithTag("NPC");
  xnpc = GONPC.transform.position.x;
  ynpc = GONPC.transform.position.y;
  znpc = GONPC.transform.position.z;
  pplayer = _RandomPressure.p;
  Hcurrent = _Label1.F * (-1) + Hinitial;
  }
  }
  void OnGUI()
  {
  s1 = NPCList.Count;
  s = s1.ToString();
  GUI.Label(new Rect(10, 10, 200, 20), s, customGuiStyle);
  }
  }

In game I always see s=0. There must be something wrong with my code. How can I make a dynamic list of class NPC?