Page 357 - clra62_0019-(GIPE)

THE IMPORTjNCE OF GENERAL STATISTICAL IDEAS 349
was not quite so high as stated. There is accordingly
a somewhat steep decline from a growth in each ten
years prior to 1860, ranging between 33 and 36 per
cent.,.to a growth first of about 25 per cent., and finally
of 2 I per cent. only. The Civil War of the early sixties
naturally occurs to one as the explanation of the break
immediately after J 860, but the effects could hardly
have continued to the present time, and a more general
explanation is suggested.·
Other special explanations have occurred to me as
partly accounting (or the change. One is that, prior to
1860, the United States at different times increased its
territory and population partly by purchase and partly
by annexation. But I cannot make out that either the
purchase of Louisiana early in the century, or the sub-
sequent annexations following the Mexican War, would
make a material difference. There is a considerable
increase certainly after the Mexican War, but it would
be difficult indeed to estimate how much of the popu-
lation of Texas and New Mexico which was then added
to the Union had previously swarmed over from the
Union, and had thus been from the first economically,
if not politically, part of the United States. Another
obvious suggestion is that possibly immigration into
the United States has fallen off as compared with what
it formerly was. But this explanation also fails, as far
as the official figures carry us. The proportion of im-
migration to the total increase of population in each
census period since 1820, previous to which I have
not been able to obtain figures, has been as follows:

Proportion o/Immigralio" 10 Total I,,",aIe 0/ Populali01l;" 1M
,mdeNllt"l;oned Periods ;" llu United Stalts.
Per Cent. Per Cent.
1820-30. • 4.7 1860-70 ..• 35.0
'30-40 • . • 14.2 '70-80. . • 24.2
'40-50 . . • 27.9 '80-90 .. • 42.1
's0-60 • • • 31.5 '90- 1 9 00 •• 29·4
Immigration. according to these figures. has thus in
late years played as important a part as it formerly did