2. Try to write in present tence not in past. You have info about something in the past, but you should describe pie charts/tendencies/lines/percents/ shares which you see now, in present. Read some analytical papers in Business Week, The Economist, WS Journal and you'll see. PRESENT TENCE!
3. In the tasks like this NEVER make the prediction. Nobody asks about the future and your opinion about it. Just DESCRIBE figures.
Hi, I do have some questions about your advices.
1. This was statistics in 1970 and 1984, why it is wrong to use past voice?
2. About the prediction, actually, many tutors recommended it if students have spare time, write a little prediction is fine, it make your essay more convincible.
Here's evidence:
ieltstips.com/ielts_test_tips/writing_test_tips/writing_test_tips.html
ieltsielts.com/ielts-writing-task-1-academic-written-response-from-start-to-finish-video/