Developing countries used to carry little weight in international tourism, but they have been constantly gaining ground since the 1970s: today they account for 35% of revenues and almost 40% of arrivals. According to forecasts, developing countries will soon become the engines of growth in the sector. Tourism will consequently be making an even greater contribution to GDP and employment in these countries. It will therefore become a powerful lever of economic development. Despite the high volatility in the sector (it does indeed react dramatically to the international economic climate), sharp global growth is expected in investments. However, in developing countries, the level of investment will only catch up with the level recorded in high income countries from 2015 onwards.