At the start of 21st century, there were about 6,000,000,000 people living in the world. Every year the population grows by another 90 million. The population of the world is unevenly spread – some parts are more densely populated than others. Some people choose to move from one place to another in search of a job or a better quality of life. However, occasionally some people are forced to move and they become refugees.indpopul