is projected to reach 8 billion in 2023, 9 billion in 2037, and 10 billion people in the year 2055.
has doubled in 40 years from 1959 (3 billion) to 1999 (6 billion).
is currently (2017) growing at a rate of around 1.12 % per year, adding 83 million people per year to the total.
growth rate reached its peak in the late 1960s, when it was at 2.09%.
growth rate is currently declining and is projected to continue to decline in the coming years (reaching 0.53% in 2050, and 0.09% in 2100) .
a tremendous change occurred with the industrial revolution: whereas it had taken all of human history up to the year 1800 for world population to reach 1 billion, the second billion was achieved in only 130 years (1930), the third billion in 30 years (1960), the fourth billion in 15 years (1974), the fifth billion in 13 years (1987), the sixth billion in 12 years (1999) and the seventh billion in 12 years (2011).
During the 20th century alone, the population in the world has grown from 1.65 billion to 6 billion.