In the forty years before World War I, according to one influential estimate, international trade increased in value at an average rate of about 3.4 percent a year; from 1914 to 1950, that rate fell to just 0.9 percent; then, from 1950 to 1973, it rose at about 7.9 percent a year before falling slightly to about 5.1 percent between 1973 and 1998.
