This represents a high degree of self-sufficiency compared to other world regions or countries, such as OECD Europe (55%) or the United States (70%). The contribution of imports needed to cover India's energy needs is, however, increasing: from a net import share of 10% in 1990 to 23% in 2007. This trend is driven by increased oil imports for the transport and industry sector. Also coal imports have been rising over recent years despite indigenous reserves, since domestic coal suffers from a high ash content and its low quality reduces power generation efficiency.