See full article and chart here -- http://www.economist.com/blogs/buttonwood/2012/02/demography
Basically, economic growth comes from having more workers, making them more productive or a combination of the two. If a country has fewer workers, productivity has to do all the work, and even then real growth is likely to be slow.
The top five growers are the Philippines, Egypt, Malaysia, Israel and india. Of course, very-rapidly growing population can be a problem, especially if you can't find jobs for young men. But it is better to be in the top half of the table - like Australia, New Zealand and Ireland - than the bottom.
These figures are quite remarkable - not since the Black Death can there have been such a fall in workers - and the implications must surely be very profound. One reason it will be so hard for Europe to grow its way out of the debt crisis is the impact of demography.