. To enhance the explanatory power of the estimation results, several indicators, such as income per capita, industry structure, urbanization rate and population density, are incorporated in the estimation equa- tions as control variables.
. Om die verklarende krag van die skatting resultate, 'n paar aanwysers, soos inkomste per capita, bedryf struktuur, verstedeliking koers en bevolkingsdigtheid verbeter, is opgeneem in die skatting lykings as beheer veranderlikes.