That's one thing that I wish was available but isn't. I wish the players rankings were documented and there is a list you could look up of their past rankings and dates changed. Would be neat to see how some of the stars of today have progressed. Someone like Sharp comes to mind with that.
For many of the modern stars, a google search such as:
"Steven Stamkos Hockeys future"
will show their initial ranking. Stamkos was a 8.0B. Surpassed that a bit