The designations employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of the Secretariat of the United Nations concerning the legal status of any country, territory, city or area; or of its authorities, or concerning the delimitation of its frontiers or boundaries. In general, statistics contained in the present publication cover a period up to 2018 and as available to the United Nations Secretariat as of 31 July 2018. They reflect the country nomenclature currently in use. The term “country” as used in the text of this publication also refers, as appropriate, to territories or areas. The designations “developed” and “developing” which appear in some tables are intended for statistical convenience and do not necessarily express a judgement about the stage reached by a particular country or area in the development process. Symbols of the United Nations documents are composed of capital letters combined with figures.