A quick glance at the Rand-McNally, "New International Atlas" seems to indicate that a the most populous band is about 20 degrees +/- 5 degrees. This band includes much of India, Bangladesh, Southern China and Mexico City.
Number 2 appears to be 45 degrees +/- 5 degrees which includes much of Europe, the populous east coast of North America and Japan. This is not very analytical, but it seems to make sense. Best regards, James E. Morrison Astrolabe web pages at: http://myhouse.com/mc/planet/astrodir/astrolab.htm
