Israel's control of land, water, trade and markets, and its specification and rigorous restrictions on what could be grown, is held responsible for the decline of agriculture as a share of West Bank GDP, and the drop of agricultural labourers in the work market from 46% to 27%, so that from 1993 to 1995 output declined by 40.12%. In the years directly preceding the Al Aqsa uprising (1998–1999) the IDF and settlers uprooted 21,705 trees throughout the West Bank and Gaza Strip. After 1967, restrictions were placed on the types of fruit tree and vegetables that could be planted, and even the importation of tractors required an Israeli permit. A trial study just after the occupation carried out on Deir Dibwan's land, rich in underground water, showed great promise as one of the best sites in the West Bank for growing oranges and bananas. An Israeli drilling permit could not be obtained, leading most of those involved in the project to emigrate to the U.S.