What is the meaning of the strength of the sun lamp? all other lamp types in blender uses a physical unit to define strength but the sun lamp has a unit less strength value.So what is the unit of the sun lamp strength if it has or if it is relative what does 1 strength mean?
This is in the documentation: 


  Strength of the lights in Watts per square meter.


Though, I'm wondering if that should be kilowatts instead of watts.