It shows what percentage of teachers were male and what percentage of teachers were female.
This is not contributing any value addition to your response. This task is aimed at assessing your report writing capabilities. So, keep your writing very concise and clear. Introduce the graphical presentation very briefly and do not elaborate on that;
The bar chart illustrates the gender distribution of teachers in different educational institutions from nursery school to university in UK in 2010.
.... this is more than enough for the intro :)Overall, the
male teachers held a large share of teaching posts in higher-level institutions whereas female teachers predominated in schools for children. In the institutions for older children and young adults, this rates were more equal.
Well, following the introduction, you need to write an Overview which explains the main trends of your chart. What you've written here is fine, but adopt a more formal reporting tone :)