That's impressive video Human Population Through Time which you will see below, describes the growth of the earth's population over the last thousand years. You will notice that it took a long time for the population explosion to happen.
To be more specific it took us 200 thousand years to reach the first one billion people, but only 200 years to hit the seven billion mark.
Watch the video with the map that tracks the growth of the world's population. The video shows how we spread around the world and highlights empires and historical events over the years.
The very interesting Human Population Through Time video to watch was uploaded to YouTube by the American Museum of Natural History or the American Museum of Natural History.
Watch it