Suvival shooter enemies wont add score - unity3d

Question

In my survival shooter tutorial, I just finished adding the ScoreManager. I copied the scripts exactly as is, but the ScoreManager will never recognize that the score has increased. I've added debugging on the ScoreManager and EnemyHealth scripts to see if the score is actually increasing, and believe me, it isn't.
Here's the EnemyHealth script:
using UnityEngine;
using UnityEngine.AI;
public class EnemyHealth : MonoBehaviour
{
public int startingHealth = 100; // The amount of health thee nemy starts the game with.
public int currentHealth; // The current health the enemy has.
public float sinkSpeed = 2.5f; // The speed at which the enemy sinks through the floor when dead.
public int scoreValue = 10; // The amount added to the player's score when the enemy dies.
public AudioClip deathClip; // The sound to play when the enemy dies.
Animator anim; // Reference to the animator.
AudioSource enemyAudio; // Reference to the audio source.
ParticleSystem hitParticles; // Reference to the particle system that plays when the enemy is damaged.
CapsuleCollider capsuleCollider; // Reference to the capsule collider.
bool isDead; // Whether the enemy is dead.
bool isSinking; // Whether the enemy has started sinking through the floor.
void Awake()
{
// Setting up the references.
anim = GetComponent<Animator>();
enemyAudio = GetComponent<AudioSource>();
hitParticles = GetComponentInChildren<ParticleSystem>();
capsuleCollider = GetComponent<CapsuleCollider>();
// Setting the current health when the enemy first spawns.
currentHealth = startingHealth;
}
void Update()
{
// If the enemy should be sinking...
if (isSinking)
{
// ... move the enemy down by the sinkSpeed per second.
transform.Translate(-Vector3.up * sinkSpeed * Time.deltaTime);
}
}
public void TakeDamage(int amount, Vector3 hitPoint)
{
// If the enemy is dead...
if (isDead)
// ... no need to take damage so exit the function.
return;
// Play the hurt sound effect.
enemyAudio.Play();
// Reduce the current health by the amount of damage sustained.
currentHealth -= amount;
// Set the position of the particle system to where the hit was sustained.
hitParticles.transform.position = hitPoint;
// And play the particles.
hitParticles.Play();
// If the current health is less than or equal to zero...
if (currentHealth <= 0)
{
// ... the enemy is dead.
Death();
}
}
void Death()
{
// The enemy is dead.
isDead = true;
// Turn the collider into a trigger so shots can pass through it.
capsuleCollider.isTrigger = true;
// Tell the animator that the enemy is dead.
anim.SetTrigger("Dead");
// Change the audio clip of the audio source to the death clip and play it (this will stop the hurt clip playing).
enemyAudio.clip = deathClip;
enemyAudio.Play();
}
public void StartSinking()
{
// Find and disable the Nav Mesh Agent.
GetComponent<NavMeshAgent>().enabled = false;
// Find the rigidbody component and make it kinematic (since we use Translate to sink the enemy).
GetComponent<Rigidbody>().isKinematic = true;
// The enemy should no sink.
isSinking = true;
// Increase the score by the enemy's score value.
ScoreManager.score += scoreValue;
// After 2 seconds destory the enemy.
Destroy(gameObject, 2f);
}
}
Here is the ScoreManager:
using UnityEngine;
using UnityEngine.UI;
using System.Collections;
namespace CompleteProject
{
public class ScoreManager : MonoBehaviour
{
public static int score; // The player's score.
Text text; // Reference to the Text component.
void Awake()
{
// Set up the reference.
text = GetComponent<Text>();
// Reset the score.
score = 0;
Debug.Log("score reset");
}
void Update ()
{
// Set the displayed text to be the word "Score" followed by the score value.
Debug.Log(score);
text.text = "Score: " + score;
if (Input.GetKeyDown(KeyCode.V))
{
score += 10;
}
}
}
}
The Score should increase when enemy dies, but for some reason it wont. I know this because in the ScoreManager I've added Debug.Log to print out the value of score every frame. I can press V (added for debug) and my score value increases, but normally it does not.