Why has the US alone held 16.54 per cent voting rights?

IMF
The International Monetary Fund is an International organization that oversees these financial institutions and regulations that act at the International level. The IMF has 189 member countries (as on 12 April 2016) but they do not enjoy an equal say. The top ten countries have more than 52 per cent of the votes. They are the G-8 members (The US, Japan, Germany, France, the UK, Italy, Canada and Russia), China and Saudi Arabia. The US alone has 16.54 per cent voting rights.