Answer:
Hey there!
From 1810 to 1930, it is 1 billion people in 80 years.
From 1930 to 1975 it is 2 billion people in 45 years.
From 1975 to 1999 it is 2 billion people in 24 years.
From 2011 to 2025 it is 1 billion people in 14 years.
However, in 1975 to 1999, the population change was still the greatest.
Let me know if this helps :)