(July 2011) Even though the world population growth rate has slowed from 2.1 percent per year in the late 1960s to 1.2 percent today, the size of the world’s population has continued to increase—from 5 billion in 1987 to 6 billion in 1999, and to 7 billion in 2011. This Population Bulletin looks at the four phases of the demographic transition as descriptive of past and future population growth. We highlight four countries to illustrate each phase and its implications for human well-being: Uganda (high birth rate, fluctuating death rate); Guatemala (declining birth and death rates); India (approaching replacement-level fertility); and Germany (low or very low birth and death rates).