More from Exceptional People:

On average, 5 percent of the populations of Britain, Ireland, and Norway emigrated every decade between 1850 and 1910, which increased to 14 percent of the Irish population emigrating between 1890 and 1910.  By the turn of the century, Italy, Portugal, and Spain recorded similar emigration levels… The Swedish population fell by 44 percent in the twenty-year period from 1871-1890.

Massive immigration dramatically impacted the economies of countries in the New World, which had relatively small populations.  Between 1880 and 1910, Argentina received the equivalent of 20 percent of its population per decade; the United States between 5 and 10 percent per decade; and Canada between 5 and 15 percent per decade.  Immigration in this age of mass migration accounted for around 50 percent of Argentina’s population increase, and about a 30 percent increase for the United States and Australia.

The question that still bedevils me is why (democracy + anti-foreign bias) didn’t swiftly regulate immigration down to a trickle.  Could 19th-century voters really have believed in open borders?