Vietnam is expecting to welcome its 100 millionth citizen next month, making it the third country in Southeast Asia to reach this milestone after Indonesia and the Philippines. The country's population has more than tripled since reunification in 1975, but it's expected to start declining by 2050 due to a low birth rate. The government has been promoting policies to encourage childbirth, but they have not been successful so far. The 100 millionth citizen will be celebrated with a nationwide campaign, and they will receive a cash prize and other benefits from the government. The government hopes that this milestone will inspire citizens to have more children and help reverse the declining birth rate.