The table below shows the annual income and the total income tax paid by an individual at different income levels.
| Annual Income | Total Tax Paid |
|---|---|
| £40 000 | £4 800 |
| £55 000 | £8 250 |
| £75 000 | £15 000 |
| £90 000 | £20 700 |
| £120 000 | £31 200 |
What is the change in the average tax rate for an individual if their annual income increases from £55 000 to £90 000?
5%5\%5%
8%8\%8%
11%11\%11%
14%14\%14%
