GDP is a matter of constant fluctuations in a country’s economy and therefore a very imporant figure in measuring the value of goods and serivices o yearly or quarterly period, so the present state of it is of a great signicifance for the future predicitons of economc power.
By comparing and analyzing GDP, economy specialists can project the future of global economic status on the basis of current and past trends. So, based on those, China will remain as one of the largest economies in the world by 2050, while the U.S. economy could fall down to 3rd place for example. So, that means at least the top 5 world economies will remain more or less at the top, and there will be some fluctuations in between them. The forecast is pretty much the same for some much closer future, say, the top 10 economies in the world by 2020 will remain USA, China, Brazil, Germany and others that you will find later down on our list of the richest countries in the world by GDP.
For the recent update and more information on this issue, you can learn more on this issue on the Insider Monkey’s article on 25 richest countries in the world by 2017 GDP.