Here's a breakdown:

* Argon makes up about 0.93% of the Earth's atmosphere.

* Nitrogen is the most abundant gas overall, at about 78%, but it's not an inert gas.

* Oxygen is the second most abundant gas, at about 21%, and is also not an inert gas.

* Neon, helium, krypton, and xenon are other inert gases, but they are present in much smaller amounts than argon.