The very low level of agricultural productivity is apparent not only within individual LDC economies, but also when compared internationally. Not only is there an agricultural productivity gap between LDCs and ODCs, but that gap has been widening. In 1990, the LDCs’ cereal yield per hectare was only 61 per cent of that of ODCs. Two decades later, the proportion was just 37 per cent (chart 40). These very low levels of productivity, combined with the strong rural concentration of the population in rural areas, are the main explanation for the pervasive poverty in these countries (UNCTAD, 2004). That pattern is driven more by expulsion forces (i.e., the dearth of gainful employment in rural areas) than by attraction forces (because of the lack of decently paid jobs in urban areas).