[ANDROID]saving data with playerprefs

Hello.

I'm making an android 2d runner game and I'm trying to save some data periodically such as high scores, total distance run, number of games played, average distance per game etc.

I'm attempting to use PlayerPrefs to do this but the problem is (I think...) that my saved keys are all rest to 0 after the app is closed and restarted.

Here is an example of my game over routine where I attempt to save some data..

 private void GameOver () {
         renderer.enabled = false;
         rigidbody.isKinematic = true;
         totalNumberOfJumps+=numberOfJumps;
         PlayerPrefs.SetFloat ("totalNumberOfJumps", totalNumberOfJumps);
         
         PlayerPrefs.SetFloat ("NumberOfPlays", numberOfPlays);
         
         GUIManager.SetTotalNumberOfJumps(totalNumberOfJumps);
         GUIManager.SetNumberOfPlays(numberOfPlays);
         
         totalDistanceRun += distanceTraveled;
         PlayerPrefs.SetFloat ("totalDistanceTraveled", totalDistanceRun);
         GUIManager.SetTotalDistanceRun(totalDistanceRun);
         GUIManager.SetHighScore(highScore);
         averageDistance = totalDistanceRun / numberOfPlays;
         PlayerPrefs.SetFloat ("averageDistance", averageDistance);
         
         GUIManager.SetAverageDistance(averageDistance);
             
         
         if(score>highScore){
             highScore = score;
             
             PlayerPrefs.SetFloat("HighScore", highScore);
             
             GUIManager.SetHighScore(highScore);
             
             
             Debug.Log (highScore);
             
         PlayerPrefs.Save();
         }
         enabled = false;
         
     }

I then attempt to read the total number of jumps at the start of my game..

 private void GameStart () {
 
 PlayerPrefs.GetFloat ("totalNumberOfJumps", totalNumberOfJumps);
 
 }

My totalNumberOfJumps variable is 0 where before the app was restarted it reflected the true number of jumps.

I can't get it to work in the Unity Editor or on Android.

What's the best way to debug PlayerPrefs on a device? Does PlayerPrefs return an error if you use GetFloat and the key does not exist?

Should I be using PlayerPrefs to store data such as this and if not, what are my alternatives?

I have no idea where PlayerPrefs stores it's data on Droid, I've read of a location but I can't find it on my rooted Galaxy S2. Does anyone know where I can find it?

Using Unity 4.2.1f4, Android 4.0.4

Edited to show full GameOver() function