A lot of them in the bin as new versions were released, I imagine.
I have been looking for early versions of the wall chart, but I've largely come up empty handed. I did find that besides the original version in 1968 there were at least two more editions: one in 1974 and the other one in 1993. However, I found no photos of the first version and only a snapshot of the others.
So, I submit to the powers of the internet. Does anyone know where to look for these old versions of the wall chart (either photos or the physical posters)?