How spawn object only once every 100 points?

Hi. I have problem with spawning PowerUp every 100 points. PowerUp not give points, just give speed to ball for 3 secs, and it must spawn only once per 100 points. And I dont have idea how to do this spawning only once every 100 points.

this is my code, but in it, powerup spawn only once in all game :

using UnityEngine;

using System.Collections;

public class BallPhysic : MonoBehaviour
{

private Vector3 ballPosition;
public GameObject playerObject;
public GameObject Terrain;
public Transform SpeedUpPrefab;
bool SpeedUpActive = true;
float TerrainX, TerrainZ, BlockWidth;
// Use this for initialization

void Start ()
{
   TerrainX = Terrain.collider.bounds.size.x;
   TerrainZ = Terrain.collider.bounds.size.z;
   BlockWidth = playerObject.transform.localScale.y;
   ballIsActive = false;
   // rigidbody.velocity = new Vector3(0f, 0f, -Speed);
   ballPosition = gameObject.transform.position;
}
void CreateNewSpeedUp()
{
  var SpeedUp = Instantiate (SpeedUpPrefab);
  SpeedUp.name = "SpeedUp";
}
IEnumerator OnTriggerEnter(Collider collider)
{
  if(collider.gameObject.name =="SpeedUp")
  {
   Destroy(collider.gameObject);
   //setSpeed(1.75f);
   //setVelocityBall();
   yield return new WaitForSeconds(3f);
   //SetNormalSpeed();
   //setVelocityBall();
   }
}

// Update is called once per frame
void Update () {
   if (Score % 100 == 0 && SpeedUpActive)
   {
      CreateNewSpeedUp();
      SpeedUpActive=false;
   }
}

}

Your attempt with mod is a good idea, you didnt post the whole code, but from your piece I see that it only spawns speedUp once because SpeedUpActive value is set to false after the first spawn; hence if (Score % 100 == 0 && SpeedUpActive) will be evaluated as false;