Answer:
0.484 billion 0.0484 billion per year
Explanation:
Population change between 1950 and 1960 = 3.039 - 2.555 = 0.484 (billion)
Number of years between 1950 and 1960 = 1960 - 1950 = 10 years
Average population change per year = 0.484 รท 10 = 0.0484 billion per year