Flash :: Massive Efficiency In Timeline Project?

this is the offending bit of code:

for (var i in yearMarkersArray) {
yearMarkersArray[i].x = ((timelines.x + 350) % 140) + (140 * i) - 5;
yearMarkersArray[i].text = "0";
}

This is part of the main loop that triggers whenever the user drags the zoomed-out timelines (the sprites in eventsArray) left or right. The six TLFText objects in yearMarkersArray appear to scroll left or right with the user, but are really repositioned and relabeled with the correct year markers as calculated by a function I did not include above (it's working and not relevant to this problem, I simply replaced it with the "0" for clarity).

The text-setting statement is the problem code...I've commented literally everything else out of the main loop to verify it. I even changed the statement to not involve any function call (simply setting the text attribute to "0"), and it still causes the final .swf to eat an extra 1% of my CPU every 15 seconds until finally the FPS crashes through the floor. The rest of the main loop has much, MUCH more complex and I'm sure inefficient code that also runs every frame,Since this project reads a data file with a list of timeline events whose span of years I cannot predict, I do need the displayed year markers to be done dynamically in some way. The code ultimately works (I only noticed the ridiculous slowdown when I accidentally left the movie open and idle for a few minutes),