Belarus (; , "Bielaruś" or "Biełaruś", ; ), officially the Republic of Belarus, formerly known by its Russian name Byelorussia or Belorussia (), is a landlocked country in Eastern Europe bordered by Russia to the northeast, Ukraine to the south, Poland to the west, and Lithuania and Latvia to the northwest. Its capital and most populous city is Minsk. Over 40% of its is forested. Its strongest economic sectors are service industries and manufacturing. Until the 20th century, different states at various times controlled the lands of modern-day Belarus, including the Principality of Polotsk (11th to 14th centuries), the Grand Duchy of Lithuania, the Polish–Lithuanian Commonwealth, and the Russian Empire. 

In the aftermath of the 1917 Russian Revolution, Belarus declared independence as the Belarusian People's Republic, which was conquered by Soviet Russia. The Socialist Soviet Republic of Byelorussia became a founding constituent republic of the Soviet Union in 1922 and was renamed as the Byelorussian Soviet Socialist Republic (Byelorussian SSR). Belarus lost almost half of its territory to Poland after the Polish–Soviet War of 1919–1921. Much of the borders of Belarus took their modern shape in 1939, when some lands of the Second Polish Republic were reintegrated into it after the Soviet invasion of Poland, and were finalized after World War II. During WWII, military operations devastated Belarus, which lost about a third of its population and more than half of its economic resources. The republic was redeveloped in the post-war years. In 1945 the Byelorussian SSR became a founding member of the United Nations, along with the Soviet Union and the Ukrainian SSR.
How much of their economic resources did they lose?
more than half