Onmouseover running multiple times while hovering on element?

Why does onmouseover run multiple times while I hover over one element?

I'm trying to run a simple animation when the user hovers over an icon but it runs multiple times.

I'm testing it here:

http://lujanventas.com/test.php

Anyway, any ideas on how to fix it? maybe using a listener instead?

This is the javascript running onmouseover:

function upIcon(n) {
    console.log("Mouseover icon: " + n);
    $('#icon' + n).animate({ backgroundPositionY : "-=15px" }, 200 );
    $('#icon' + n).animate({ backgroundPositionY : "+=15px" }, 200 );
    }