Writing about graph

I would be grateful if you could correct my writing errors. it's ielts writing task 1.

The line graph indicates the number of people who had visited four international museums in millions between 1980 and 2015.

Overall, the two most popular museums (Louvre and Vatican) had an increase in the number of visitors, whereas, the trend for Shenzhen museum remained stable with slight fluctuation and the callers in London museum fell moderately.

According to the graph, Louvre museum which had most visitors, stood at 8 million in 1980, then the number of visitors with fluctuated trend reached almost 9.6 million in 2015. There was a gradual rise in the number of visitors for Vatican museum by 4 million, starting from 1980 to 2015.

With regard to the graph, the number of visitors in museum leveled off at 4 million from 1980 to 1985. Then it declined steadily of 2 million in 2015.

The number of visitors in Shenzhen museum stood at just less than that in London museum in 1980, then 1990 saw slightly decline near 3 million in number of visitors. Again it was just as same as that in London museum during 1990 to 1200. Further by ascending constantly returned to near 4 million in 2015.