This depends on how your copying and communication practices are monitored. Institutions that choose not to keep records of everything they copy, but elect to participate in a survey, pay an annual fee per student. As the administrative burden of sampling is considerably less than full record keeping, almost all institutions choose this option.
Institutions that keep records of every copy they make, pay a fee for each minute copied. This per minute fee will vary according to the type of program that is copied (programs that are likely to be kept as an ongoing resource cost more per minute than those that are more ephemeral in nature).
For further information about the cost of obtaining a Screenrights licence, please contact us.