Setup: An Orc have a javelin as their ranged attack weapon.  How many javelins do an orc carry?

Question: I have not seen rules when the creature stat block includes a 'throwable' weapon what the amount of the item.  I want to know if there is a generally accepted practice on determining the amount carried?   

In general it is "enough"

But this is from the intro of the MM/Basic Rules:

Ammunition

A monster carries enough ammunition to make its ranged attacks. You can assume that a monster has 2d4 pieces of ammunition for a thrown weapon attack, and 2d10 pieces of ammunition for a projectile weapon such as a bow or crossbow.

Thank you!!