A research study shows that in the US, 50% of PCs are left on overnight, resulting in an estimated annual energy waste of 28.8 billion kWh, and a cost of $2.8 billion per year. User behaviour is slightly different in Europe, with approximately 28% of PCs being left on overnight in the UK, resulting in an estimated energy loss of 2.5 billion kWh, costing £300 million per year. In Germany, with approximately 30% of PCs left on overnight, it is estimated 4.8 billion kWh of energy are wasted each year, costing €919 million[10] There is a significant market in third-party Power Management Software offering features beyond those present in the Windows operating system.[11][12][13]