The General Assembly launched a 10-year campaign to bring safe water and sanitation to all the world's people by the year 1990. Called the International Drinking Water Supply and Sanitation Decade, 1981-1990, the drive is designed to assist 2.5 billion people requiring good water or sanitation services, or both. The World Health Organization estimates that some 60 percent of the inhabitants of developing countries lack ready access to safe water and that 75 percent have inadequate sanitation. The success of the drive depends on the launching by national governments of their own programs. Estimates for the total cost range from $300 billion to $600 billion.