In 1840, Asia was the dominant area with more than 50%, followed Europe at around 38%, while the figure for the rest of the world was lowest, only one-fifth compared to Asia.
Europe had an resurged trend, by 1880, the figure for it decreased significantly to nearly 35%, followed by a rapid decline to about 22% , before sugered to approximately 38% in the end of the period.
Conversely, the figure for Asia showed the reverse rates. With the rise to precisely 30% in 1920, after which it exhibited a notable increase to more than 10%, and a final decline slightly to just under 40%.
An unstable trend can be seen in the figure for the rest of the world. Growing sharply and accounted for the largest proportion ( about 48% ) in 1880, but latter dropped to approximately 39%, and kept plumeted to only about 25% in 2000
