The two pie charts from the year 2000 detail historic population age in Yemen in Italy, and there are a further two charts providing a comparative projection for 2050. There are three age groups represented, with both countries displaying a decline in the proportion of younger populations and a converse increase in older populations.
First of all, in 2000, the majority of people in Yemen were aged 0-14, with 50.1%, compared with 46.3% 15-59 year olds and only 3.6% of people aged 60 plus. In Italy, however, child population is much lower, with only 14.3% of people aged between 0 and 14. This leaves the vast majority of people (61.6%) between 15 and 59, and a much higher proportion (24.1%) of people aged over 60.
Looking ahead to 2050, the Yemeni population is predicted to alter significantly in age, with 15-59 year olds expected to be in the majority, at 57.3%, compared with 37% 0-14 year olds and 5.7% over 60. In Italy, however, the percentage of both 15-59 year olds and 0-14 year olds will have fallen by 2050, with projected figures of 46.2% and 11.5% respectively. This then means that proportion of over 60s will have increased dramatically, almost doubling to 42.3%, which represents by far the largest predicted change.
In this model answer, I have chosen to divide my paragraphs in to 2000 / 2050. However, you could also choose to divide them in to Italy / Yemen. If you do this, then you can use language to describe change over time in each paragraph (increase / decrease). I have also chosen to clearly represent every figure as a percentage, but you could use roughly / approximately etc. and talk about double / half.