As the older edition items get harder to find (especially in collectable conditions), is there some sort of industry supported metric or statistical analysis that guesstimates a percentage of how many items may be removed (destroyed by accident or thrown out) from the 'pool' in any given year?  Something that may have be a 2 on the Acaeum's scale back in 2001 is really a 3 today due to natural losses.  I've been looking for some time but have come up with nothing in my searches.

Thanks

-SKA