Dhaka was declared the national capital by the Constituent Assembly of Bangladesh in 1972. The post-independence period witnessed rapid growth as Dhaka attracted migrant workers from across rural Bangladesh. 60% of population growth has been due to rural migration. The city endured socialist unrest in the early 1970s, followed by a few years of martial law. The stock exchange and free market were restored in the late 1970s. In the 1980s, Dhaka saw the inauguration of the National Parliament House (which won the Aga Khan Award for Architecture), a new international airport and the Bangladesh National Museum. Bangladesh pioneered the formation of the South Asian Association for Regional Cooperation (SAARC) and hosted its first summit in Dhaka in 1985. A mass uprising in 1990 led to the return of parliamentary democracy. Dhaka has hosted a trilateral summit between India, Pakistan and Bangladesh in 1998; the summit of the D-8 Organization for Economic Cooperation in 1999 and conferences of the Commonwealth, SAARC, the OIC and United Nations agencies during various years.