Playerprefs resetting after quit

Hey! I'm having a problem with my code. My game is currently using 2 scripts, a GameManager (attaches to camera) and a SunScript (attached to a prefab (Sun) that is instantiated every 1 second onto the screen). When you click on the Sun, it destroys the gameObject and adds 10 points to your score, which I save using playerprefs, and then displays it using OnGUI.

The problem: when I quit the application and re-open, it displays the correct amount, but when I click on a Sun, it resets the counter. PLEASE HELP!

Here is the GameManager script:

 using UnityEngine;
 using System.Collections;
 
 public class GameManager : MonoBehaviour {
     public GameObject sunPrefab;
     private float rateDrop = 2f;
     public static float totalCurrency;
     public static float collectAmount = 152f;
     public GUISkin skin;
 
     void Start(){
         GenerateSun();
         Debug.Log(PlayerPrefs.GetFloat("Total Currency"));
     }
 
     void InstantiateSun(){
         Instantiate (sunPrefab, new Vector2(Random.Range(-6.0f, 0f), Random.Range(10.0f, 12.0f)), Quaternion.identity);
     }
 
     void GenerateSun(){
         InvokeRepeating ("InstantiateSun", 1f, rateDrop);
     }
 
     void OnGUI (){
         GUI.skin = skin;
         GUI.Label(new Rect(Screen.width/2 - 40, 10.0f, 40, 20), PlayerPrefs.GetFloat("Total Currency").ToString(), skin.GetStyle("Counter"));
     }
 
     void OnApplicationQuit(){
         PlayerPrefs.SetFloat("Total Currency", PlayerPrefs.GetFloat("Total Currency"));
     }
 }

And here is the SunScript:

using UnityEngine; using System.Collections;

public class SunScript : MonoBehaviour { public GameObject particles;

 void Update(){
     if(transform.position.y < -15.0f){
         Destroy(gameObject);
     }
 }

 void OnTriggerEnter(Collider other){
     if(other.transform.tag == "House"){
         Debug.Log("I hit the house!");
         Destroy(gameObject);
     }
 }

 void OnMouseDown(){
     Collect();
 }

 void Collect(){
     Instantiate (particles, transform.position, Quaternion.Euler(270,0,0));
     Debug.Log(PlayerPrefs.GetFloat("Total Currency"));
     GameManager.totalCurrency += GameManager.collectAmount;
     PlayerPrefs.SetFloat("Total Currency", GameManager.totalCurrency);
     Destroy(gameObject);    
 }

}