Creating Loading Bar For web Player

I have the following code setup so that my level does not load till everthing is ready but how do I add a loading bar. This is in C#.

My Code:

     public float percentageLoaded = 0; 
     
     public Texture2D background;
     
 
     
     void OnGUI()
     {
         
     
         GUI.DrawTexture(new Rect(0,0,Screen.width,Screen.height), background);
     }
     
     void Update() 
     {      
         if (Application.GetStreamProgressForLevel("Demo") == 1)  
         {
             guiText.text = "";
         Application.LoadLevel("Demo");
         }
             else 
     {          
             percentageLoaded = Application.GetStreamProgressForLevel("Demo") * 100;        
             guiText.text = percentageLoaded.ToString();    
     }  
         
   }
     
     
 }