Ohm. Because of that surface resistivity and the surface resistance are often mixed up. In order to differentiate between the two, surface resistiv-ity is often expressed also in Ohm/square (Î©/sq.) which is not a valid unit from the dimensional anal-ysis point of view. 2 Surface resistivity and surface resistance 2.1 Current density and surface cur-
The median age of the world's population was estimated to be 30.1 years in 2016, with the male median age estimated to be 29.4 years and female, 30.9 years.
Age structure of population: 1  30.5 percent between the ages of 0-14 years. 2  64.3 percent between the ages of 15-64 years. 3  5.2 percent are 65 years and older.