This is an interesting interactive article hosted on the BBC website.
The article asks two pieces of information from you, the first is the country you are in and the second your pre-tax monthly wage. It then calculates your wage against your own countries average wage and the global average wage.
The URL for this interactive is - http://www.bbc.co.uk/news/magazine-17543356
Its also worth while visiting that master of statistics, Hans Rosling at gapminder – http://www.gapminder.org. Check out the Wealth and Health of Countries – which relates well to the Global pay scale question.
If you have a spare hour, I wold recommend that you check out the Joy of stats video, broadcast on the BBC and hosted on the Gapminder site.