Pendulum data are published on 15 June. Pendulum data is taken from the a-order and the Population Register and includes persons employed in the reference week, the reference week from 2015 is the week containing the 16th of November. Commuters are persons who have a different municipality of residence municipality on the last day of the statistical month (30/11). For some groups, the workplace municipality is set equal to the municipality of residence. This applies to employees in the defense, maritime workers and employees in the industry "labor hire". Furthermore, employees without permanent employment will be registered with the workplace municipality they are administratively descending. This applies in particular to persons in the construction industry and transport industry. Incorrect registration of employees on business or insufficient breakdown of the business in the register may cause significant errors for a few municipalities. For some groups employed permanently, there will also be problems with real residence. This applies inter alia to weekly traders and students.