Final answer:
The average rate of population growth between 1950 and 2000 is not provided, but there are other population growth rates mentioned in the given information.
Step-by-step explanation:
The average rate of population growth between 1950 and 2000 is not provided in the given information. However, there are other population growth rates mentioned in the information you provided. For example, between 1965 and 1980, the world population grew at an annual rate of 2%, suggesting a doubling time of 36 years. It is also predicted that population growth slowed to a 1.1% rate during the 2005-2015 period, implying a doubling time of 65 years. These rates give an indication of how the population growth rate has changed over time.