Please review my IELTS task 1 writing

I'm preparing for IELTS and need help improving my writing, thank you.

The prompt:

The graph below gives information about how much people in the United States and the United Kingdom spend on fuel.

Summarise the information by selecting and reporting the main features, and make comparisons where relevant.

My essay:

The line graph shows data regarding fuel expenditure between people of the United States and the United Kingdom.

Overall, the spending in relation to the percentage of income rises in the United Kingdom the richer people get. Whereas the trend is the opposite of the United Kingdom's in America. The spending on income ratio of each nation converges at approximately four percent as people transition from middle-income to high income.

According to the data, people of the United Kingdom's poorest group spend the least, less than one percent of their income on fuel. In contrast to that of American people, which is around 4 to 5.5 percent. The ratio rises as people approach the middle class, ranging from around 2.5 to 4 percent. From that point on however, the ratio stops increasing and fluctuates around four percent in the richest group.

In the United States, the general trend is that the poorest spends the most on fuel, around four to little less than six percent as mentioned above, and the richest spends the least, from 4% to between 3% and 2%. The middle class spends less and less as people get richer, dropping from five to little over four percent.