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.
According to the 2010 revision of the World Population Prospects the total population was 2 283 000 in 2010, compared to only 485 000 in 1950. The proportion of children below the age of 15 in 2010 was 36.4%, 59.9% was between 15 and 65 years of age, while 3.7% was 65 years or older .