Intermediate demand is that which comes from other enterprises. The level of intermediate demand depends on the nature of the requirements for services of enterprises which purchase them. In this connection, structural changes in the economy, which are reflected in the product mix and in the production processes, must be examined in more detail. The significance of service functions within firms in highly developed economies has changed substantially over the last decade or so, leading various authors to discuss the emergence of a ‘new economy’. The demand for services is influenced by the fact that new types of services are offered by the use of information technology. The transformation of the economies of highly developed societies is direcdy connected with a decline in importance of specifically production activities, accompanied by a simultaneous increase in service functions. The most useful indicator for the tertiarization of the economy is provided by the structure of employment by occupation.