In any economy every year there are millions of transactions which combine to give the overall level of economic activity. The development and use of Keynesian economics gave a great impetus to national income analysis during and after the Second World War with Richard Stone, Nobel Laureate 1984, as the leading figure. The central point of national income analysis is the measurement of the amount of economic activity or national product: that is, the value of all goods and services crossing the production boundary. Net national product subtracts an estimate of depreciation from the gross measure, and is a more accurate reflection of the achievement of the economy. The former relates to all economic activity taking place within the geographical limits of the economy. The latter measures economic activity carried out by the resources - labour and capital owned by national members of the economy.