1N4736A Zener Diode: How to Determine Izmax and Izmin for Voltage Regulator Design?

For demonstration of simple electronic voltage regulator using Zener diode, I use the following Zener Shunt Regulator
circuit. This is to check the voltage regulation from minimum possible RL to no load condition. 
For deciding Rs and RLmin, I need to know Izmax and Izmin of the zener diode 1N4736A used. From this data sheet, there are different current specifications available. Maximum working current is given as 133mA. Again test current at working voltage is 37 mA. Somewhere, I found if zener works continuously at maximum working current, it will get damaged. Also, somewhere minimum zener current is taken as 10% of maximum zener current whereas somewhere it is taken as the knee current (1mA) at which zener impedance is tested. Which is the correct choice?

You have to consider power dissipation (I*V) at the higher currents, normally additional copper on the PCB helps, but there are practical limits there as well. There is also an impedance (slope) associated with the zener, delta V/delta I, this limits how well the zener regulates the voltage over the range of desired current. Operating at the knee is a region where the impedance is undergoing rapid change. These factors determine a practical range over which the zener is operated,cheers,Richard