Other Factors Considered Network Externalities The Commission notes that in the study, no surcharge was applied to account for the network externality. This is mainly because of the lack of an accepted method for evaluating it with any certainty, and mainly because of the lack of a practical mechanism to ensure that any such surcharge would be used to support the acquisition and retention of marginal subscribers. Definition of Active Mobile Subscribers The Commission notes the market dynamics and the indication in the report that there is increasing competition evidenced by new products and services. The Commission notes that despite the impressive growth, the penetration rate is still low. The Commission directs that mobile operators shall now report active subscribers, defined as subscribers who have used a revenue generating service within the preceding 90-day period. 5. THE DETERMINATION The Commission hereby determines the Interconnection rates to be applied among the fixed and mobile telecommunication operators in the Republic of Kenya. The appropriate cost-based interconnection rates shall be as per table below: 5