premise: The UN study found that the gross national product (GNP) for the West Bank and Gaza Strip fell 8.6 percent during 1996, when the territories were sealed almost continually following a spate of Islamic suicide bombings in Israel.
  Israel started the practice of closing the territories in response to unrest in 1993 under the leftwing Labor party. The damages caused by the closures include lost wages for day laborers, lost trade revenues and uncollected taxes.
  The number of Palestinians authorized to work in Israel hit a peak of 139,200 in 1992, falling to zero for much of 1996.
  Since the latest closure imposed after a suicide bombing in Tel Aviv on March 21 which killed three Israelis, only three thousand Palestinians are currently authorized to work in Israeli-contolled industrial zones adjacent to the territories.
   What caused the latest closure?
hypothesis: a suicide bombing in Tel Aviv on March 21