It’s now almost five years since Lehman Brothers collapsed, precipitating a global financial crisis. In the US, one group has fared significantly better than the rest as the country struggles out of recession – the richest 1 per cent.

Recent data from the Internal Revenue Service shows that the incomes of the richest 1 per cent of Americans increased by 31 per cent between 2009 and 2012, while the incomes of the bottom 99 per cent grew less than 1 per cent. There’s a good Economist chart to illustrate this here. The share of national income flowing to the richest 1 per cent has now reached a record high of 19.3 per cent.

So how does this compare internationally? The UK has little reason to feel smug. According to a report this February by the Resolution Foundation, the richest 1 per cent of Britons own 10 per cent of national income.

The Organisation for Economic Cooperation and Development (OECD) warned earlier this year that inequality was increasing across its 34 member countries. It has rated its members according to levels of inequality using the Gini coefficient (which measures the extent to which the distribution of income varies from perfect equality.) The UK ranks 28th out of 34 countries, and the US fares even worse at 31. Only Turkey, Mexico and Chile are more unequal than the US. Meanwhile Slovenia, Denmark and Norway are three OECD nations with the most equal income distribution. You can find the full list here.

The Gini coefficient can’t distinguish between different distributions of inequality, in that it doesn’t tell you if inequality is high because the top 1 per cent hold a huge proportion of national wealth, or if the majority of the country’s wealth is held by the top 25 per cent. The Gini coefficient also depends on up-to-date GDP data, which is especially hard to extract from developing countries. This can sometimes make comparison hard.

The CIA world fact book, for instance, compares 136 countries in terms of inequality, but some of the data it uses is over 15 years old. Here the US ranked 95th out of 136 in terms of inequality, with the UK in 76th place, and Sweden, Slovenia and Montenegro topping the list. The most unequal countries were Lesotho, South Africa and Botswana.

One conclusion that can be drawn is that both the UK and the US may be wealthy nations, but compared to their wealthy peers they stand out because of the wide gap between rich and poor. This has all kinds of implications. Rising inequality raises moral questions about fairness and social justice, and some researchers believe that inequality holds back economic growth. There’s also a worry that as the economic power of the richest 1 per cent increases, their political power increases with it.

In the US, for instance, the richest 1 per cent pay 37.4 per cent of income taxes – leaving the world’s superpower worryingly dependent on the financial fortune of just 1.35 million tax payers. Similarly in the UK, 30 per cent of government tax revenue comes from just 308,000 earners in 2012.

