Inequality in the USA has risen significantly over the last three decades, according to the latest figures released by the Congressional Budget Office (CBO).

The Trends in the Distribution of Household Income Between 1979 and 2007 report, which was published this week, reveals a number of worrying trends. The data shows that after-tax income increased by 275% for the richest 1% of the population during the 28 years in question. The poorest 20%, meanwhile, recorded gains of only 18% over the same period.

The study also revealed that between 2005 and 2007, the years immediately leading up to the global financial crisis, the top 20% of the population earned more after-tax income than the entire bottom 80%.

A poll conducted by the New York Times and CBS News, meanwhile, highlights growing dissatisfaction among Americans regarding the country's economy. Almost half of those asked said they thought the sentiment behind the Occupy Wall Street protests reflected the views of most Americans, whilst two-thirds said wealth should be more evenly distributed in the US.

Quoted by the BBC, Democratic House Representative Sander Levin commented on the data: "The rules have been changed by the unfair tax policies of the last decade and our tax code is doing less to level the playing field than it was in the past."

This growing inequality, particularly when considered in conjunction with the rising poverty rate in the US, seems certain to provide businesses and politicians alike with food for thought in the coming years.