When at least one of the underlying values of `NumberOfUnits` is reported `NumberOfUnits` MUST also be reported. `NumberOfUnitsExcludingLivingSpace` at the end of the fifth period MUST exist at least once. `NumberOfUnitsExcludingLivingSpace` at the end of the first period MUST exist at least once. `NumberOfUnitsExcludingLivingSpace` at the end of the fourth period MUST exist at least once. `NumberOfUnitsExcludingLivingSpace` at the end of the second period MUST exist at least once. `NumberOfUnitsExcludingLivingSpace` at the end of the third period MUST exist at least once. `NumberOfUnitsLivingSpace` at the end of the fifth period MUST exist at least once. `NumberOfUnitsLivingSpace` at the end of the first period MUST exist at least once. `NumberOfUnitsLivingSpace` at the end of the fourth period MUST exist at least once. `NumberOfUnitsLivingSpace` at the end of the second period MUST exist at least once. `NumberOfUnitsLivingSpace` at the end of the third period MUST exist at least once. `NumberOfUnits` MUST be equal to the summation of the underlying values. `NumberOfUnits` at the end of the fifth period MUST exist at least once. `NumberOfUnits` at the end of the first period MUST exist at least once. `NumberOfUnits` at the end of the fourth period MUST exist at least once. `NumberOfUnits` at the end of the second period MUST exist at least once. `NumberOfUnits` at the end of the third period MUST exist at least once.