Effect of Subclassing on swf size


Can anyone explain the following…

I have a class that is huge: ‘BaseClass’. For arguments sake lets say it is 5k.

In my Swf I use 10 classes that all subclass BaseClass, each is only 1k.

When I compile the swf, do each of these subclasses gain the weight of BaseClass, or do they share it?
ie. do all 10 subclasses become 6k each (making a total of 60k), or do they share the BaseClass (10 X 1k + 5k ) = 15k?

(I know my example is unrealistic, but hopefully you get my point).