Query: The constitution was amended to reduce the President's power in what year?
Context: According to the Constitution, executive power is exercised by the President of the Republic and the Government. From the Constitutional amendment of 1986 the President's duties were curtailed to a significant extent, and they are now largely ceremonial; most political power thus lies in the hands of the Prime Minister. The position of Prime Minister, Greece's head of government, belongs to the current leader of the political party that can obtain a vote of confidence by the Parliament.