"population aged 65 and over" - writing graph

This graph chart illustrate thet the population aged 65 and aver between 1940 and 2040 in Japan, Sweden and USA.Firstly,Japan population aged 65 and over is under 5 percentage between 1940 and 2000 but after in 2000 population of aged 65 and over graduated between 2000 and 2040.Secondly,Sweden population of aged 65 aged over fluctuate between 1940 and 2040.The last country is USA 's population aged 65 and over is increase between 1940 and 1980.In 1980 and 2010 population is satbile after that population of aged 65 and aver is rise.To sum up , population aged 65 and over increase between 1940 and 2040.

I'm confused as to what this response is for, but assuming they are observations made from some sort of graph, there are a few things you could to to make your response more clear.

Try using either "graph" or "chart" since they mean similar things
"This graph illustrates the population of people 65 and older between the years of 1940 and 2040 in Japan, Sweden, and the United States.

Introduce your observations
I noticed that between 1940 and 2000, Japan's population of seniors is under 5%.

Secondly, between 1940 and 2040, Sweden's population of seniors tends to fluctuate while the United States shows an increase between 1940 and 1980.

In conclusion, although variations between countries occur, the overall population of adults 65 and older in the world increases between 1940 and 2040, according to the graph.

Thanks for your feedback