The operation called Services survey provides economic information for the calculation of the main macro-magnitudes of the professional and business services sector, and it serves as an auxiliary base for creating the Input-Output Tables and the Economic Accounts of the Basque Country. The economic information is provided by establishments whose main activity, measured in terms of added value generated, are the professional, scientific & technical activities and administrative & auxiliary services activities sections according to the National Classification of Economic Activities, even where their head offices or management offices are outside of the Autonomous Region.