I think that $2 is purchasing-power-parity adjusted (they talk about "international-$"), which is even less in real dollars.

For an anecote on PPP vs real dollars, I remember that in the eighties in soviet-ruled Poland, an average monthly salary amounted to about $20. At the same time, the average standard of living was not that bad: most families had flats with central heating (no air-con though), education up to university level and healthcare were free, most families didn't have cars but public transport was cheap.