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 the 1960's the growth of the U.S. population aged over 65 has been twice that of the general population. By the year 2000, the number of men and women over age 65 in the U.S. is projected to increase to 32 million people, which will be approximately 20% of the population. The old-old population, those over the age of 75, is actually increasing the fastest.