The South Africa Company administered the territory of Northern Rhodesia from 1891 until take-over by the UK in 1923. During the 1920s and 1930s, advances in mining spurred development and immigration. The name was changed to Zambia on independence in 1964. In the 1980s and 1990s, declining copper prices and a prolonged drought hurt the economy. Elections in 1991 brought an end to one-party rule. But the subsequent vote in 1996 saw blatant harassment of opposition parties. The election in 2001 was marked by administrative problems with at least two parties filing legal petitions challenging the results. Opposition parties currently hold a majority of seats in the National Assembly.