Thaksin's second term was less successful. On 26 December 2004, the Indian Ocean tsunami occurred. In addition to the human toll, it impacted the first-quarter Thai GDP in 2005. The Yellow Shirts, a coalition of protesters against Thaksin, also emerged in 2005. In 2006, Thaksin dissolved the parliament and called for a general election. The April 2006 general election was boycotted by the main opposition parties. Thaksin's party won again, but the election was declared invalid by the Constitutional Court. Another general election, scheduled for October, was cancelled. On 19 September a group of soldiers calling themselves the Council for Democratic Reform under the Constitutional Monarchy and led by Sonthi Boonyaratglin organized a coup, ousting Thaksin while he was in New York preparing for a speech at the United Nations General Assembly. During the last year of the second Thaksin government, the Thai GDP grew by 5.1 percent. Under his governments, Thailand's overall ranking in the IMD Global Competitiveness Scoreboard rose from 31st in 2002 to 25th in 2005 before falling to 29th in 2006.