AddCount.cs

using UnityEngine;
using System.Collections;

public class AddCount : MonoBehaviour
{
	[SerializeField]
	Sample data;
	
	void OnGUI ()
	{
		GUILayout.Label (data.count.ToString ());

		if (GUILayout.Button ("add")) {
			data.count += 1;
		}
	}
}

Sample.cs

public class Sample : ScriptableObject 
{
	public string data;
	public int count;
}