The document discusses four scenarios for what Singapore's population and demographics may look like in 2050 based on different fertility rates and levels of annual net migration. Scenario 2, with a fertility rate of 1.24 births per woman and 30,000 net annual migrants most closely matches Singapore's current situation, resulting in a total population of 4.89 million, with 3.1 million working age adults and a ratio of 2.7 working adults per elderly person. Former Prime Minister Lee Kuan Yew said that an annual intake of 20,000 to 25,000 migrants is politically digestible for Singapore.