A Possible Formula for Q

 

  If one calculates and plots Q/I one gets the following curve.

This looks somewhat like an exponential decay function and if we try to fit one we get the following. The value for λ was chosen by eye.

We will have to wait and see if this exponential factor gives a good long term fit. One can think of it as a saturation term that might explain why I peaks when it does. So our observations suggest,