One thing to keep in mind, there are different types of doubling. There is die deterioration doubling, caused by a well used die that is wearing out, there is mechanical doubling caused by a slight shift in the die while the coin is being struck, and there is doubled die doubling caused by a doubled image on the die from when the die is made. The only one that has any value is the doubled die, but the other forms are very common. Where do you see the doubling on your coin?