How? If Epic does not give that information for us, the sellers, how can we share it? And to honesty, I am starting to think that it is not worthy the effort. For example, on my site, I had just one sell month, while my system were downloaded 331 times from a pirate site. Someone here bought it and shared overthere. 
Last month I had, on my site around 30 purchases.
And since my system is made with blueprint, anyone can download, copy the code and make his own game, without paying me for my work.
And you can find over there almost every item on marketplace.
So, for me it is not worthy! I will finish implementing some features and then I will let it die. I had plans to add other products, like better AI, and other templates, but no… Waste of time! And I can not work for free, because I don’t have anyone to pay my bills.