Get perfect scroll percentage

i want get scroll percentage form 0 to 250 point having a Line large 95px and dragger large 10px. I make this script but it dont perfect to get value. It’s fast to update value.

EXAMPLE HERE
http://megaswf.com/view/bf8c19e0a076b297897386a8d733ba9f.html

dragger.onPress = function() {
dragger.startDrag(false, 0, -14, line._width-dragger._width, -14);
this.onEnterFrame = updateValue;
this.onMouseMove = updateEvent;
};
function updateEvent() {
updateAfterEvent();
}
dragger.onRelease = dragger.onReleaseOutside=function () {
dragger.stopDrag();
delete this.onEnterFrame();
this.onMouseMove = “”;
};
function updateValue() {
var drag_x, max_x;
drag_x = dragger._x;
max_x = line._width-dragger._width;
** perc = Math.max(min_value, Math.ceil((drag_x/max_x*max_value)));**
_root.perc = perc;
}
//
max_value = 250;
min_value = 0;
updateValue();

HOPE your reply soon. thank you

I attach fla.