The return of democracy and government reforms beginning in 1986 were hampered by national debt, government corruption, coup attempts, disasters, a persistent communist insurgency, and a military conflict with Moro separatists. During Corazon Aquino's administration, U.S. forces withdrew from the Philippines, due to the rejection of the U.S. Bases Extension Treaty, and leading to the official transfer of Clark Air Base in November 1991 and Subic Bay to the government in December 1992. The administration also faced a series of natural disasters, including the eruption of Mount Pinatubo in June 1991. After introducing a constitution that limited presidents to a single term, Aquino did not stand for re-election. Aquino was succeeded by Fidel V. Ramos. During this period the country's economic performance remained modest, with a 3.6% percent GDP growth rate. Political stability and economic improvements, such as the peace agreement with the Moro National Liberation Front in 1996, were overshadowed by the onset of the 1997 Asian financial crisis.