The line graph compares changes in the percentages of people more than over 65 living in three different countries over a period a century between 1940 and 2040.
Overall, the USA was the most popular type of country in the size of the population throughout the survey, while the remaining two countries remained less significant during the period.
At the beginning, 1940, the amount of population above 65 in the USA was the most common with a contribution of nearly 10% and the proportion of the populace grew slightly to exactly 10%. This was followed by another substantial increase in 1980 while in the following decades it decreased minimally and maintained the same level until 2020. However, this downward trend experienced a dramatic rise and had hit a peak of around 25% by 2040.
Ultimately, the level of boomers living in Sweden was initially higher than that for the population living in Japan. However, the former rose remarkably and gradually while the latter saw a slight decline and remained unchanged till 1990. Afterwards, the remaining of 3% surged significantly and steadily. Then the proportion of boomers in Japan contributed to 10% whereas the share of the populace over 65 in Sweden grew dramatically and had reached to 20% by 2010, although there was an unexpected drop. Finally, both trends boomed enormously and had hit their highest level by 25% and 27% over the rest of the period. 
The line graph compares  
changes
 in the percentages of  
people
 more than  
over
 65 living in three  
different
 countries  
over
 a period a century between 1940 and 2040. 
Overall
, the USA was the most popular type of country in the size of the population throughout the survey, while the remaining two countries remained less significant during the period.
At the beginning, 1940, the amount of population above 65 in the USA was the most common with a contribution of  
nearly
 10% and the proportion of the populace grew  
slightly
 to exactly 10%. This  
was followed
 by another substantial increase in 1980 while in the following decades it decreased  
minimally
 and maintained the same level until 2020.  
However
, this downward trend experienced a dramatic rise and had hit a peak of around 25% by 2040. 
Ultimately
, the level of boomers living in Sweden was  
initially
 higher than that for the population living in Japan.  
However
, the former rose  
remarkably
 and  
gradually
 while the latter  
saw
 a slight decline and remained unchanged till 1990. Afterwards, the remaining of 3% surged  
significantly
 and  
steadily
. Then the proportion of boomers in Japan contributed to 10% whereas the share of the populace  
over
 65 in Sweden grew  
dramatically
 and had reached to 20% by 2010, although there was an unexpected drop.  
Finally
, both trends boomed  
enormously
 and had hit their highest level by 25% and 27%  
over
 the rest of the period.