Studies that attempt to explain the impact of biofuel demand on world food prices exhibit marked differences in their findings, which suggest that demand could explain anywhere from 15 to 70 per cent of the 2007-2008 food price hike. Direct competition between food and fuel has led to calls for support for a new generation of biofuels that do not compete with food (Vos, 2009). The share of total overseas development assistance (ODA) allocated to agriculture fell from a peak of 18 per cent in 1978 to 4 per cent in 2009, with ODA earmarked for agriculture having decreased significantly in the 1990s (United Nations, 2008a) (see figure III.6).