Duplicating instances at certain amount apart

Hello, im still learning some of this actionscript stuff and was stuck on somthing.

Right now i have a movie clip i named game. I want this to be duplicated up to 15 times, but i want there to be 5px between the two of them on the _y axis.

to do the duplication i used
for (i=0; i<15; i++) {
_root.game.duplicateMovieClip(“game”+i,i);
}

but im not really sure how to get the instances where i want them to go from here…