The secondary sector accounted for 22.60% of GDP and a general workforce of 800,000 employees in 2009. There are several reasons for this stagnation, ranging from consecutive occupations, political turmoil and the War in Kosovo in 1999. The electricity sector is considered as one of the sectors with the greatest potential of development. In April 2020 Kosovo with KOSTT, the government-owned Transmission System Operator, declared its independence from the Serbian electricity transmission operator Elektromreža Srbije with a vote by the European Network of Transmission System Operators for Electricity, ENTSO-E, which has paved the way for Kosovo to become an independent regulatory zone for electricity. The vote confirms that a connection agreement will be signed between ENTSO-E and KOSTT, allowing KOSTT to join the 42 other transmission operators. A joint energy bloc between Kosovo and Albania, is in work after an agreement which was signed in December 2019. With that agreement Albania and Kosovo will now be able to exchange energy reserves, which is expected to result in €4 million in savings per year for Kosovo. Kosovo has large reserves of lead, zinc, silver, nickel, cobalt, copper, iron and bauxite. The nation has the 5th largest lignite reserves in the world and the 3rd in Europe. The Directorate for Mines and Minerals and the World Bank estimated that Kosovo had €13.5 billion worth of minerals in 2005.