A high proportion of primary commodities in national exports significantly increases the risk of a conflict. A country at "peak danger", with commodities comprising 32% of gross domestic product, has a 22% risk of falling into civil war in a given five-year period, while a country with no primary commodity exports has a 1% risk. When disaggregated, only petroleum and non-petroleum groupings showed different results: a country with relatively low levels of dependence on petroleum exports is at slightly less risk, while a high level of dependence on oil as an export results in slightly more risk of a civil war than national dependence on another primary commodity. The authors of the study interpreted this as being the result of the ease by which primary commodities may be extorted or captured compared to other forms of wealth; for example, it is easy to capture and control the output of a gold mine or oil field compared to a sector of garment manufacturing or hospitality services.