How are the sales percentages calculated?

I’m still new to selling, but I’d really like to know how the percentages are calculated. When I click on the info next to the percentage, it just says that the percentages change based on sales volume. Where can I find more detailed information about this? And at what point do you actually become a “top seller”?

At the moment, everyone gets 70% commission - this applies across the board to all patterns / sellers. This is the maximum rate - the remaining 30% is split between PayPal fees, marketplace development, advertising, and much more. 

Top Seller status is assigned manually - i.e. when the patterns are particularly popular or particularly professionally designed. After a few sales, you too should receive this status.

Thanks for the answer :-)
I didn’t really want to know the exact breakdown—I just wanted to know what it means that the percentage is based on sales figures ;-)
But it’s nice to know that I could reach Top Seller status quickly :-)