The assessment of social and economic vulnerability of countries and territories to reef loss is based on exposure to reef threats, reef-dependence, and adaptive capacity. Eighty-one countries, 21 island territories, and six subnational regions (Florida, Hawaii, Hong Kong SAR, Peninsular Malaysia, Sabah, and Sarawak) were assessed, and are categorized according to quartiles (low, medium, high, and very high). Reef territories that are only inhabited by military or scientific personnel are not included.