Other estimates in the literature end up around the same level: e.g. 51% (Fischer et al, 2007) to 60% (Fraiture et al., For the manufacturing sector and for electricity production, OECD 2008 calculations were used as the starting point. While water use in different industrial sectors can vary significantly, an overall average relationship with total industrial value added was assumed per geographical region, according to assumed regional structure of the sector and technological level. Over time this relationship was adapted according to assumed structural sector shifts and technological progress. A water balance can be established for each grid cell (see Chapter 1), taking account of land-use patterns, natural vegetation, crop distribution and management, climate parameters (temperature, precipitation and CO2 concentration), and soil parameters. This shows the resulting run-off per grid cell, i.e. the amount that ends up in river systems, lakes and dams, and the volumes available for downstream extraction.