The present report is based on data obtained primarily from the annual reports questionnaires (ARQ) received by UNDCP up to February 1999. Such reports hitherto presented only the supply side data from the ARQ. The present report now contains a statistical summary of the demand side data obtained from the ARQ, and is meant to show one of the several ways in which UNDCP is trying to put the "balanced approach" (putting demand on par with supply) into practice. While the supply side dimensions of the international drug problem have been recognized for decades, the demand side has traditionally been considered a domestic issue, not conducive to international assessment. Thus, data on supply side indicators such as illicit drug cultivation, production and seizures, has been systematically collected and published for most of this century. Indicators to measure the demand for illicit drugs, such as the extent and incidence of abuse, or the treatment and prevention of it, have not received commensurate attention at the international level.