The source of information was as following: – with regard to buildings and dwellings completed — a report on completed residential buildings and dwellings in non–residential buildings (form B–07), – with regard to dwellings which construction has begun — a report on residential construction (form B–06), – with regard to dwellings for which permits have been granted or which have been registered with a construction project — a report on building permits and registrations with a construction project granted for construction of buildings (form B–05).