Let's take the best case scenario: a,b,c,d, and e are all 9.

Upon substituting these numbers in..

and this is your maximum value.

Now, if we take it down one notch: a,b,c,d,e are all 8. The value you get is around 900. Big step down, huh? And remember, the probability of getting all of them to be 8 is relatively low. This makes it almost inevitable that most of the values will be concentrated the the lower region of the graph.