Districts are required to be reapportioned every ten years following the federal census in order to be of substantially equal population. However, from 1902 until 1962, the General Assembly ignored this provision. It was estimated that by that point that some districts in the Memphis area had approximately ten times the population of some in rural areas. In 1962 this issue was taken to court. Despite U.S. courts having traditionally declined to rule on such issues, the US Supreme Court opted to hear this case and ruled that the legislature had to comply with the state constitution, as its failure to do so was in violation of the Equal Protection Clause of the Fourteenth Amendment to the U.S. Constitution (see "Baker v. Carr"). Subsequent litigation has further refined the rules regarding this; in the late 1990s a majority-black district in rural West Tennessee was required to be created.