____ 1) Total
____ 2) Of which rooms used solely for the purpose of conducting economic activity

Field 1) Total should be used to indicate all rooms in the dwelling, which compels with the definition of the chamber provided above, even if the rooms are presently used for not accommodation-related purposes, such as: to operate economic activity, to store old items, as well as if they are not used at all.
Multifunctional rooms, being combination of kitchen and guest room should also be taken into consideration.
Field 2) of which rooms used solely for the purpose of conducting economic activity- should be used to indicate rooms, which are used as headquarters of various companies, offices, workshops, studies, etc. The fact, whether the economic activity is conducted by a person residing in the dwelling, or a person not being an inhabitant or owner of the dwelling, but leased a part of it is of no importance.

Note:
Chambers (and other rooms) which are used to conduct economic activities, which have a separate entrance from the street, yard or shared porch should not be considered parts of the room, even if they are connected with the inhabitable part of the dwelling. They should not be considered as rooms of the dwelling, and their floor space should not be indicated in total usable floor space.