The compilation of National Accounts is a complex process built up to meet the need for an ever more complete representation of national economies and, at the same time, to the need for an estimate of Gross National Product (GNP) as harmonized as possible across EU. The publication of the inventory offers to all the users of macroeconomic data the opportunity of delving into estimation methods of GNP and its components following the three approaches of production, income and expenditure, into procedures aimed at assuring the exhaustiveness of the estimates, into techniques ensuring the consistency of estimates obtained using independent approaches, and into the sources and the classifications actually adopted. Methods, sources and classifications presented here have been employed for the general revision of estimates which, assuming year 2000 as a benchmark, have been compiled and issued by Istat from December 2005.Custodian: ISTAT - ISTITUTO NAZIONALE DI STATISTICA (Italy)