Data on private household spending are based on the Budget Survey conducted annually since 1978 (except in 2001 and 2002). The Budget Survey is a sample survey conducted in two sessions. The first session focuses on large expenditure. Each year, approximately 6 thousand households participate in the survey for a period of three months. In the second session, about 1,800 households are asked to provide information on all their expenses, including periodical expenses. In the second session, households participate for a period of two weeks.