Random drop rate problem

var itemDrop : GameObject;
var enemyHealth : int = 1;

var dropRate : float = 0.25; //25% chance of dropping

function OnCollisionEnter(theCollision : Collision)
    	if (theCollision.gameObject.tag == "Player")
    		enemyHealth -=1;
    		if(enemyHealth <= 0)
    			if(Random.Range(0,1) <= dropRate)
    				var pickupDrop = Instantiate(itemDrop, gameObject.transform.position, Quaternion.identity);

Above is the code I have for my random drop rate, when I destroy my enemies I would like it to have a 25% chance of dropping my item, but as I have it now, it happens all the time.

Can anyone point out where I’m going wrong please?

Your Random.Range numbers need to be floats, not integers. So your if statement should look like this: if(Random.Range(0f,1f) <= dropRate)

Because your Random.Range function takes integers as input it returns an integer.
And as per this page Random.Range script reference, it is always outputing zero, which is always less than dropRate.

Hence, you always get a drop.

Use float values for min and max range to get random float number.