Following the ESA 2010 guidelines, in national accounts two types of units and two corresponding ways of subdividing the economy are used : (a) institutional unit ; (b) local kind-of-activity unit (local KAU). The first type is used for describing income, expenditure and financial flows as well as balance sheets. The second type of units is used for the description of production processes, for input-output analysis and for regional analysis. An institutional unit is an economic entity characterised by decision-making autonomy in the exercise of its principal function. A resident unit is regarded as constituting an institutional unit in the economic territory where it has its centre of predominant economic interest if it has decision-making autonomy and either keeps a complete set of accounts, or is able to compile a complete set of accounts. A local KAU groups all the parts of an institutional unit in its capacity as producer which are located in a single site or in closely located sites, and which contribute to the performance of an activity at the class level (four digits) of the NACE Rev. 2. An institutional unit comprises one or more local KAUs ; a local KAU belongs to one and only one institutional unit.

National accounts data are usually compiled for years and quarters. In general, the ESA 2010 transmission programme requires data starting in 1995 (years) and 1995Q1 (quarters) but some series start later. If backwards data exist, they may have been compiled according to earlier versions of ESA and can present conceptual breaks with those compiled under ESA2010. Annual national accounts data starting : Table 1 (GDP from production, expenditure and income approaches), Table 1 (employment) : 1949 ; Table 1 (population) : 1990 ; Table 1 (final consumption expenditure of households by durability), Table 5 : 1959 ; Table 1 (exports and imports) : rest of the world = 1949 ; B0, U2, U3, D0 =1990 ; Table 2 and 3 : 1978 Table 8 (Annual) : 1949 (most of the data ) Table 9, NTL, 1100 : 1995 2000, 2200, 2600, 1978 2900 : 2015