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.
1 In 2010, women accounted for 57 percent of the population age 65 and over and for 67 percent of the population age 85 and over. 2  The United States is fairly young for a developed country, with 13 percent of its population age 65 and over in 2010.