IELTS 1 - Please help me check

The line graph describe the needed time on average to manufacture car at the four different companies in the US from 1998 to 2005.

Overall, the average time spent to produce cars in both factories decreased. In the needed time terms, Honda needed the least time to produce one car.

In 1998, General Motor needed 32 hours on average to produce a car, which was the highest point in the whole line graph, while 28 hours was the average time to make a car in Ford factory. The time figures for Toyota and Honda were similar, at 22 hours on average. Throughout the remainder of the period, there was a gradual decline in the average time spent by General Motor to produce car, which reduced to 22 hours by the year 2005, whereas the figure for Ford was around 21 hours after minor fluctuations.

Over the same period, the number for Honda and Toyota varied significant, but it was much lower than the figures for Ford and General Motor. From 2001 to 2002, there was a similar increase in the amount of time to make a car in Honda and Toyota, from 22 hours to 2003 hours. However, the time reduction in these factories were gradual by 20 hours in 2005.