The graph below shows the proportion of the population aged 65 and over between 1940 and 2040 in three different countries

The line graph compares the percentage of elderly aged 65 and above among three countries during a 100 years period.
It can be seen from the graph that the figures for old people increases in each country from 1940 to 2040. However, Japan seems to face some surprising changes throughout the given period.
Starting in 1940, 9% of Americans were aged 65 and over, as opposed to around 7% of Swedish citizens and 5% of Japanese citizens. The figure for elderly Americans and Swedish rose gradually in the next 50 years reaching around 15% in the year 1990. On the other hand, Japan recorded just under 5% of its population aging over 65 in that year.
Predictions mention a huge jump in the figure for Japan between 2030 and 2040. By 2040, it is expected that around 27% of the Japanese population will be of 65 years old and above, while the figures for Sweden and the USA won't differ a lot, with about 25% and 23% respectively.