You didn't give us a list of countries to choose from, but I can at least do this much for you. According to the United Nations' report on "World Population Prospects," there are nine countries that are predicted to account for half of the world's projected population increase by the year 2050: India, Nigeria, Democratic Republic of the Congo, Pakistan, Ethiopia, the United Republic of Tanzania, the United States of America, Uganda and Indonesia.
Does having that list help you with your question?