To improve your writing you need to make sure that your ideas, both in sentences and paragraphs, stick together or have coherence and that the gap between ideas is bridged smoothly. One way to do this is by using transitions - words or phrases or techniques that help bring two ideas together. Transitional words and phrases represent one way of gaining coherence. Certain words help continue an idea, indicate a shift of though or contrast, or sum up a conclusion. Check the following list of words to find those that will pull your sentences and paragraphs together.
I normally don’t have time to comment on writing but I will give you a quick comment. The content is all fine. The overview gives the key features and the body paragraphs give the detail. However, it is long. Could you really write this in 20 mins? Also try grouping information together in the body paragraphs “The number of postgraduates going on to part time work and further studies is almost the same (2,535 and 2,725 respectively)”. This way you avoid repetition of your sentences. Also if you look at the first chart, there is considerable difference between part time work and further studies which could be mentioned in the body.
All the best