It's estimated that the world's entire population, 1,000 years ago, was 300,000,000 - about the same number as the United States in 2006. In 1804, eight hundred years after reaching the 300 million mark, the world's population arrived at one billion people for the first time - it then took another century, in 1927, to hit 2 billion. The twentieth century, however, saw the world's population numbers skyrocket; 3 billion in 1959, 4 billion in 1974; 5 billion in 1987, 6 billion in 1998, and then 7 billion by the end of 2011. It was estimated there were 8 Billion(!) of us by the end of 2022. The United Nations estimates the world's population will reach approximately 10 billion by 2100. At this time the world averages around 200,000 births each and every day - the equivalent of one-and-a-half cities the size of Los Angeles being added to the planet every single month! As of this writing China, India, and the United States remain the most populated countries on the planet with India expected to pass up China in 2025...