Demographics of the world
According to the CIA - The World Factbook, the country with the highest birth rate currently is Niger at 51.26 births per 1000 people. The country with the lowest birth rate is Japan at 7.64 births per 1000 people. Hong Kong, a Special Administrative Region of China, is at 7.42 births per 1000 people. As compared to the 1950s, birth rate was at 36 births per 1000 in the 1950s, birth rate has declined by 16 births per 1000 people. In July 2011, the U.S. National Institutes of Health announced that the adolescent birth rate continues to decline.
Demographics of Bangladesh
Bangladesh has the highest population density in the world, excluding a handful of city-states and small countries with populations under 10 million, such as Malta and Hong Kong. The total fertility rate (TFR) has been reduced by more than two thirds since Independence. Current TFR in Bangladesh is 2.1 which means that women have 2.1 children on average in their lifetime. At this TFR and without migration, country's population will eventually be neither growing nor shrinking, once the top of its age pyramid fill in.
Most of the demographic statistics below are from the CIA World Factbook, unless otherwise indicated.