The first bar charts compares students of different ages in terms of why they study and the second chartcompareswhether they are supported by an employer different levels of support from employers.
the proportion of students
However,
However is an inappropriate word. You could use "Also" instead.
both younger groups
You should mention the ages of the groups.
receives by more than 50 per cent
less by under 47 per cent than both former groups
this proportion is still higher
students aged 30-to-39
A more details looked at the bar graph reveals that the proportion of study purposes is not always similar.
This sentence could be removed.
out for of interest purpose
Therefore, while is seen from the overall groups, student age 40-to-49 shows the similar percentage of study purpose.
This sentence is pretty confusing.