Could you help me correct this sentences?

I am preparing for IELTs test. This is a writing task 1.
Could you help me correct this sentences?

The bar graph shows the changes in the number of cars from 1971 to 2007 with intervals of 4 years.
Overall, it is clear that the population of car ownership steadily increased over the period of 36 years from 1971. The largest rise in car ownership was the proportion of British owning two cars. By contrast, the significant drop was shown for no cars. The rest of two figures for one car, and three or more cars almost remained at the similar level over the period given.
In 1971, British having no car made up almost 48%, making its level the highest, followed by one car, two cars, and three or more cars, at almost 45%, 8%, and 10%. However, no car in car ownership nose-dived from approximately 48% to 25%, whereas, in the same period of time, the figures for two cars considerably jumped from about 8% to 28%, overtaking the people not having cars in 2007. British who own one car remained the highest from around 1975 to 2007, at almost 45%, ever since ownership of no car kept on dropping. The figure for three or more cars was on increase without any drops but didn’t show much difference in percentages, rising only by 6% until 2007 from 2% in 1971.

The bar graph shows the growth of renewable energy consumption from 1950 to 2000. Given the period time, it is clear that the total energy consumption was on increase with fluctuations, reaching 2-fold larger amount in 2008 than in 1948. Overall, the largest consumed amount of source was hydroelectric power, followed by wood, biofuels and wind. The unit is measured in Quadrillion Btu.
At the start of the period, wood was the most consumed renewable energy at about 1.7 Quadrillion Btu with the slightly less used wood at approximately 1.6 Quadrillion Btu. They are the most widely used renewable energies throughout the period shown. As far as hydroelectric power, this energy source had a large impact on the total consumption, considering the fact that the two graphs’ trends are almost synchronized to each other with similar dips and hikes. For woods, the consumption remained steady at 1.8 Quadrillion Btu without almost no change until 1976, and following that it hiked to 2.4 Quadrillion over the period from 1976 to 1980. This level was kept for 10 years until 1990 and slipped to around 2 Quadrillion Btu. In terms of Biofuels and wind, they started emerging new renewable energy from 1980, reaching about 1.8 Quadrillion Btu and 0.5 Quadrillion Btu respectively in 2008. The figures had mere increments in the beginning. However, from 2000, the graphs showed exponential growth, suggesting that they will overtake the two major energies or at least be at the same level as them in the future.