Electricity generation. The production of electricity in 2013 was 23,322TWh. Sources of electricity were coal and peat 41%, natural gas 22%, hydroelectric 16%, nuclear power 11%, oil 4%, biomass and waste 2% and other sources 4%.
The nine Supreme Court Justices on the Supreme Court of the United States are the final arbiters on whether or not a law passed by the legislative branch is constitutional.
The number of Supreme Court justices has changed over the years, Kathy Arberg, spokesperson for the U.S. Supreme Court, told Live Science. The number of justices has been as high as 10. [8 Supreme Court Decisions that Changed US Families] Congress increased the number to seven in 1807, to nine in 1837, then to 10 in 1863.