In 1929, there were slightly more than two billion people living on the planet; today, there are 6.7 billion, and in 2050 there will be nine billion.
V roce 1929 žily na zeměkouli něco málo přes dvě miliardy lidí; dnes je jich 6,7 miliard a v roce 2050 jich bude 9 miliard.