Table 2.

Changes per year of four forces driving changes in water use in the U.S. agricultural and manufacturing sectors, 1970/95

Sector	i	p	a	c	t
National	0.2%	1.0%	1.5%	−2.3%
Agr	0.1%	1.0%	1.5%	−0.7%	−1.7%
Mfg	−1.9%	1.0%	1.5%	0.6%	−5.0%

In all lines, i, p, and a are the national changes of water withdrawal, population, and GDP per capita. In line National, −2.3% is the change in water withdrawal per GDP, c + t. In lines Agr and Mfg, c is the changing index of agriculture or manufacturing per GDP. The t is changing water withdrawn for irrigation per all agricultural production or changing industrial water use—except thermoelectric power—per manufacturing (data sources: World Bank for GDP, U.S. Geological Survey for water withdrawal, and Statistical Abstract of the U.S. for indices).