The industrial sector contributes 25% to the GDP of Pakistan, with a major concentration of industry in an arc stretching from Karachi to Hyderabad. 75% of Sindh's industry is located in the Karachi-Hyderabad region. The Sindh Industrial Trading Estate, home to 439 industrial units, was established on the outskirts of Hyderabad in 1950 which prospered with until the urban violence of the 1980s. Much of the city's industrial base was weakened by ethnic violence in urban Sindh in the 1980s, although poor infrastructure and supply of electricity has also hampered growth.