Or there is the comparison of nurses per head of population, where a figure for UK population was divided by a figure for the number of nurses - obtained from the Department of Health in London.
For example, if 20 percent of check engine light problems reported came from a certain vehicle but it made up only 10 percent of the vehicle population it would have an index of 2.00 (20 percent divided by 10 percent).
With a population of 2.7 million, Mongolia, the most sparsely populated country of the world is divided into 21 aimags (provinces) which are in turn divided into 239 soums (districts).