Add revenue doesn't come,why?

First of all I am really new to unity adds. I just realized the 1.38$ I made came from germany with 25 impressions and 10 completed, meanwhile I have 306 impressions and 66 completed in Turkey and I made 0$. Can someone explain me why?

It typically takes 5,000 impressions before earning any revenue from ads.
See http://forum.unity3d.com/threads/unity-ads-everyplay-how-i-make-money.268590/ for more info

@tanoshimi , but why did I get 1.38$ from 25 impressions in germany? I am only asking this. Thanks for the answer,though.