What is the composition of the atmosphere

Nitrogen accounts for 78% of the atmosphere, oxygen 21% and argon 0.9%. Gases like carbon dioxide, nitrous oxides, methane, and ozone are trace gases that account for about a tenth of one percent of the atmosphere.

This what it said when I look it up

Nitrogen is 78% of the atmosphere, oxygen 21% and argon 0.9%. That is about a tenth of one percent of the atmosphere.