When a million people swarmed onto the streets of Brazil last June there was consensus that the protest was a phenomenon of the "new middle class"- squeezed by corruption and failing infrastructure. As the Thai protests continue, these too are labelled middle class: office workers staging flash mobs in their pressed shirts.
But what does middle class mean in the developing world? About three billion people earn less than US$2 per day, but figures for the rest are hazy. Now, research by the International Labour Organisation (ILO) economists shows the rapid growth of what they term "the developing middle class" - a group on between US$4 and US$13 a day.
This group has grown from 600 million to 1.4 billion; if you include about 300 million on above US$13 a day, that's now 41 per cent of the workforce, and on target to be over 50 per cent by 2017. But in world terms they're not really middle class at all. That US$13 a day upper limit corresponds roughly to the poverty line in the US in 2005.
The ILO researchers adopted a rough definition of the lifestyle of the sub-US$13 group. The key markers were: families had access to savings and insurance, were likely to have a television in the home and to live in smaller households (four people). They would typically spend 2 per cent of their income on entertainment - plus they would have better access to water, sanitation and electricity.