The Economist constructed this overview of those countries in the world that are forecasted to have the highest GDP growth rate as well as those that have the most negative rate. As you can see the developing countries are forecasted to grow the most. From economic theory this can be explained by the fact that these countries still have a lot growth potential, because their economies are still small. Another reason why countries may see high growth is because they are located near China, as China is growing fast the country invests a lot in neighboring countries. Mongolia and Macau (a small country similar to Hong Kong also inside China) are examples. Another reason why a country may grow fast is that it is recovering from a disaster like a natural disaster or a war, of which Libya is an example.
On the other hand developed countries are growing a lot less and consequently all the forecasted fastest contracting countries are developed countries. Notice that all the fastest contracting countries, besides Syria and Iran, are located in Europe.
Due to a request by the Economist this graph has been removed.