Public subsidies for agricultural production and agrochemical inputs exacerbate environmental pressures by encouraging intense chemical use, the expansion of agriculture to sensitive areas, and overexploitation of resources (OECD 2004). The Agricultural Subsidies indicator measures subsidies as a proportion of agricultural value. For countries where this data is available, the authors use the Nominal Rate of Assistance (NRA), defined as the price of a product in the domestic market, less its price at a country’s border, expressed as a percentage of the border price, and adjusted for transport costs and quality differences. Organisation for Economic Co-operation and Development. 2004. Environmental Performance Review of Canada - Good Progress, Much to be Done. Paris: OECD.