If health lower than 0 display gui

How do I display gui saying "You died" If the health is lower than 0?

 #pragma strict
 
 var tex1 : Texture;
 var tex2 : Texture;
 var tex3 : Texture;
 var tex4 : Texture;
 
 var health : float = 100.0;
 
 private var maxHealth : float = 100.0;
 private var enterCollider : boolean = false;
 
 //Damage Collider
 function OnTriggerEnter (Col : Collider)
 {
     if(Col.gameObject.tag == "Player")
     {
         enterCollider = true;
         Debug.Log("Is inside collider");
     }
 }
 
 function OnTriggerExit (Col : Collider)
 {
     if(Col.gameObject.tag == "Player")
     {
         enterCollider = false;
     }
 }
 
 function Update ()
 {
     //Health countdown whilst in the damage collider
     if(health > 0 && enterCollider == true)
     {
         health -= Time.deltaTime * 20;
     }
     
     //Normal health regeneration
     if(health >= 0 && enterCollider == false)
     {
         health += Time.deltaTime * 2;
     }
     
     //When health reaches 100, set to maxHealth
     if(health > maxHealth)
     {
         health = maxHealth;
     }
 }
 
 function OnGUI ()
 {
     if (health <= 100)
     {
         GUI.DrawTexture(Rect(0,0, Screen.width, Screen.height), tex1);
     }
     
         if (health <= 80)
     {
         GUI.DrawTexture(Rect(0,0, Screen.width, Screen.height), tex2);
     }
     
         if (health <= 40)
     {
         GUI.DrawTexture(Rect(0,0, Screen.width, Screen.height), tex3);
     }
     
         if (health <= 10)
     {
         GUI.DrawTexture(Rect(0,0, Screen.width, Screen.height), tex4);
     }
 }