The indicator shows the proportion of school trips of all trips for the transport modes bus (function 730), county ferry (function 731), boat routes (function 732) and subway and tram (function 734). School trips: Number of trips for students in primary and secondary school. Data source: KOSTRA form 50 County transport. All journeys: Number of eligible passengers for bus, county ferries, boats, subway and tram. Data source: KOSTRA form 50 County transport.