Dit word bereken deur [brothers_only], die aantal mense met slegs broers, en [sisters_only], mense met slegs susters en [both], mense wat broers en susters het, van die totale aantal mense af te trek.
It is calculated by taking the total number of people minus [brothers_only] people that have brothers only, minus [sisters_only] that have sisters only and minus [both] that have sisters and brothers.