To help compare sizes of different surface areas, here is a list of areas of the order of 1017 square metres, i.e. between 100 billion km2 and 1 trillion km2. See alsoareas of other orders of magnitude.
... the age of 18, 6.3% from 18 to 24, 32.3% from 25 to 44, 21.1% from 45 to 64, and 11.8% who are 65 years of age or older. The median age is 37 years. For every 100 ...