First Author:   Håvard Hungnes Statistics Norway havard.hungnes@ssb.no         Second Author: Terje Skjerpen Statistics Norway terje.skjerpen@ssb.no         Third Author: Jørn Ivar Hamre Statistics Norway jorn.ivar.hamre@ssb.no         Fourth Author: Xiaoming Chen Jansen Statistics Norway jansen.xiaoming.chen@ssb.no