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.
Since 1985, the rate of women having their first child between age 40-44 has risen steadily, though it's still far below that for women ages 35-39: CDC. Rates for all births, not just of a first child, to women over 35 have been rising over the past 20 years, while birth rates for younger women are stable or declining. Still, the majority of births are to women under 35, about 85% of the total in 2013.