In 1950, a North Korean invasion began the Korean War, which saw extensive United States-led U.N. intervention in support of the South, while China intervened to support the North with Soviet assistance. After the war's end in 1953, the country's economy began to soar, recording the fastest rise in average GDP per capita in the world between 1980 and 1990. The June Struggle led to the end of authoritarian rule in 1987 and the country is now considered among the most advanced democracies in Asia, with the highest level of press freedom. However, corruption and political scandals have become growing problems in recent years; all three living former South Korean presidents have been sentenced to prison for various crimes ranging from abuse of authority to bribery and embezzlement; with two still currently serving their sentences.