Sikkim receives most of its electricity from 19 hydroelectric power stations. Power is also obtained from the National Thermal Power Corporation and Power Grid Corporation of India. By 2006, the state had achieved 100 per cent rural electrification. However, the voltage remains unstable and voltage stabilisers are needed. Per capita consumption of electricity in Sikkim was approximately 182 kWh in 2006. The state government has promoted biogas and solar power for cooking, but these have received a poor response and are used mostly for lighting purposes. In 2005, 73.2 per cent of Sikkim's households were reported to have access to safe drinking water, and the state's large number of mountain streams assures a sufficient water supply.