Switch Statements

What's wrong with my Switch Statement?

 var block : GameObject;
 var faster : GameObject;
 var smoke : GameObject;
 var slower : GameObject;
 var numberOfBlocks : float = 10.0; 
 var timeBetweenBlocks : float =2.0;
 var BlockNumber : int = 0;
 
 function Update () {
 if (numberOfBlocks > 0){
 numberOfBlocks--;
 var position = Vector3(0, Random.Range(-5, 5), Random.Range(10, 300));
 BlockNumber = Random.Range (1, 5);
 
 print (BlockNumber);
 
 switch (BlockNumber){
     case ("1"):
 Instantiate(block, position, Quaternion.identity);
 break;
     case ("2"):
     Instantiate(faster, position, Quaternion.identity);
     break;
     case ("3"):
     Instantiate(smoke, position, Quaternion.identity);
     break;
     case ("4"):
     Instantiate (slower, position, Quaternion.identity);
     break;
     case ("5"):
     print ("No block this time");
     break;
 
 }

It generates a random number, but doesn't actually make anything.