Actually the highest selling game of all time is Tetris, which I would have never guessed. And second best selling game is Minecraft which is not surprising at all. GTA V hold in the third spot. And in my country the average monthly salary is 200 euros .
Tetris ? that's ridiculous. I guess it's because of mobile sales. If Rockstar could somehow find a way to port GTA V in its full form to mobile platforms I think they could at least exceed Minecraft in sales.