Unity2D：敵の種類を増やす

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class EnemyGenerator : MonoBehaviour
{
    public GameObject enemyPrefab;
    public GameObject enemyPrefab2;


    // Start is called before the first frame update
    void Start()
    {

    }

    // Update is called once per frame
    void Update()
    {
        if (Random.Range(0, 300) == 1)
        {
            Vector3 pos = new Vector3(Random.Range(-2.8f, 2.8f), 5.5f, 0);

            Instantiate(enemyPrefab, pos, Quaternion.identity);
        }
        if (Random.Range(0, 100) == 1)
        {
            Vector3 pos = new Vector3(Random.Range(-2.8f, 2.8f), 5.5f, 0);

            Instantiate(enemyPrefab2, pos, Quaternion.identity);
        }
    }
}