The indicator shows the number of passenger kilometers per. 1,000 inhabitants for the various functions within KOSTRA Transport (bus function 730, county ferry function 731, boat routes - function 732 and subway and tram / city rail function 734). Passenger kilometres: Number of eligible passengers multiplied by average travel length. Data source: Form 50, KOSTRA-Transport. Population: Number of inhabitants in the counties at the end of the year. Data source: Statistics Norway's population statistics.