Come back Mr Fukuyama, all is forgiven.

In his 1992 book “The End of History and the Last Man”, American political scientist Francis Fukuyama famously argued that all states were moving inexorably towards liberal democracy. His thesis that democracy is the pinnacle of political evolution has since been challenged by the violent eruption of radical Islam as well as the economic success of authoritarian countries such as China and Russia.

Now a study by Russian investment bank Renaissance Capital into the link between economic wealth and democracy seems to back Fukuyama.

Looking at 150 countries and over 60 years of history, RenCap found that countries are likely to become more democratic as they enjoyed rising levels of income with democracy virtually ‘immortal’ in countries with a GDP per capita above $10,000.

” Only five democracies above the $6,000 income level have died. Even democracies above the $6,000 level have a 99 percent chance of sustaining their political system each year. The only exceptions were the military coups in Greece in 1967 ($9,800), Argentina in 1976 ($8,180) and Thailand in 2006 ($7,440), and the events in Venezuela in 2009 ($9,115), as well as Iran in 2004 ($8,475),” RenCap global chief economist Charles Robertson writes.

The $6,000 per capita GDP seems to be a crucial level, marking the point where a country is likely to shift to democracy. Tunisia, which early this year triggered the wave of uprisings against autocracy across the Arab world, recently crossed that threshold.