U.S. Department of Energy Press Release, Feb. 3, 2014.
http://energy.gov/articles/new-energy-efficiency-standards-external-power-supplies-cut-consumers-utility-bills

"The Energy Department today announced new efficiency standards for external power supplies. Over the next 30 years, these standards will help cut carbon pollution by nearly 47 million metric tons – equivalent to the annual electricity use of 6.5 million homes – and save families and businesses nearly $4 billion on their energy bills."