Handwriting animation - how to reduce filesize?

Hi…

I have created an animation that looks as if some text is being hand written… done the usual way by erasing bit by bit and then reverse whole sequence…

My problem is that there was about 7 long words in total and there ended up being about 550 frames… so now my filesize is about 650k and i havent even started the rest of the animation…

how could i reduce this and still keep a decent quality effect of the text being hand written?