s behind the expansion of water resources during the 20th century are population growth and increased per capita demand, the increase in irrigated agriculture and industrial development. It has been estimated that at least 54% of accessible runoff is already appropriated for human use, a figure that could rise to 70% by 2025 (Gleick, 1998). Globally the withdrawals of water for irrigation account for some 70-75% of the total while about 20% is for industry and the remainder for domestic use (see Table 5.7). In general, per capita water consumption in developed countries has been decreasing in recent years, reflecting the changes in forms of economic activity and the (relatively) more efficient use of the available water abstracted. In the United States, total per capita withdrawal peaked in the 1980s at about 2 700 m 3 /p/a, while actual consumption stands at about 500 m 3 /p/a. In spite of this it has been estimated Table 5.7. Global water use Cubic kilometres Agriculture Withdrawal 1 100 Consumption 1 750 Industry Withdrawal Consumption Domestic Withdrawal Consumption Total Withdrawal 1 400 Consumption INFRASTRUCTURE TO 2030: TELECOM, LAND TRANSPORT, WATER AND ELECTRICITY - ISBN 92-64-02398-4 - © OECD 2006 5. THE IMPACTS OF CHANGE ON THE LONG-TERM FUTURE DEMAND FOR WATER SECTOR INFRASTRUCTURE that, assuming a "business as usual" scenario, a significant number of both developed and developing countries will experience moderate to high water stress. Per capita water availability will continue to decline. The Drinking Water Supply and Sanitation Decade of the 1980s (1981-90), which focused primarily on the underserved populations (80% in rural areas), resulted in nearly USD 100 billion in investments (WHO, 1992), and as a result water sector performance improved. By the end of the decade 1 104 million people had obtained access to safe water, the majority being in rural areas (Dieterich, 2004). Moreover, the number of city dwellers in the developing world with access to adequate water increased by 80%. This still 