The populations of highly industrialized countries may be considerably influenced by influx of refugees, the assumption can be that the population of the industrialized countries is stagnating. On the other hand, the population's demographic composition will change radically. the percentage of senior citizens will increase by up to 1% per year. While young people will fall drastically. On the 21st century. There will be fewer young people and more active 'younger senior citizens' with time and money on their hands who will set the tone in the leisure and travel market.