population By djvila 50 1th century 256 million habitants Jan 1, 1200 1200 384 millions 1300 14th century killed thousand of people 1650 15th 516 million habitants 1750 16 th century before the industrial revolution 791 millions habitants 1800 17th century 890 million people Jan 1, 1900 18th century 1.2 million people 1950 2.5 billion 2000 6 billion 2015 7.3 billion 2025 predicted 8 billion