Believers of Abiogenesis: What was the early atmosphere made of?

I've tried looking for this online but it never says, all it ever talks about is that oxygen/ozone wasn't present. I really just want to know what you/scientists think the Earth's atmosphere (not just their little experiment, the entire planet) was composed of. It doesn't have to be exact, I'm not going to misquote you on a tiny detail and throw it in your face. I want to know general numbers of what gases, like 75% nitrogen, .3% Argon, whatever, etc. If you want to know why I want to know you can ask, but I think it's fairly important.