Donald Trump has flip-flopped on policy positions and performed about-turns in his political views. But the former real-estate mogul has remained steadfast in one matter: his refusal to release his tax returns.

Mr Trump based his presidential bid on his talents as a businessman, without revealing the details of his financial affairs. So the question of what is in Mr Trump's tax returns - and why he won't publish them - has simmered on.

Last night Rachel Maddow on her MSNBC show published details from two pages of Mr Trump's 2005 tax return.

So what can we learn from these documents?

1. Trump paid $38m (£31m) in tax on more than $150m (£123m) income

The figures show that Mr Trump paid an effective tax rate of 25 per cent on earned income.

Data from the Congressional Joint Committee on Taxation shows that this rate is well above the roughly 10 per cent the average American tax payer pays each year. But below the 27.4 per cent that taxpayers earning more than one million dollars a year average were paying at the time.

Mr Trump has previously boasted that he pays as little tax as possible. The White House said in a statement yesterday that he was "one of the most successful businessmen in the world, with a responsibility to his company, his family and his employees to pay no more tax than legally required".