CYCLICAL FLUCTUATIONS IN MIGRATION 139 
CHART 27 
RELATIVE FLUCTUATIONS IN NUMBER OF IMMIGRANTS AND NON- 
IMMIGRANTS, CLASSIFIED, BY SEX: 1905-1924. 
Only the relative slope, not | 
TOTAL IMMIGRA*™S the vertical position, of these 
curves Is significant: 
0 a 
gd \ 
IS 
\ SCALES OF 
PERCENTAGE 
FEMALE IMA I57ARTS 20 EANGE 
I 160 
120 
80 Decrease 
TOTAL NONIMMIGRA! 75° 40 
20 4 
3 o 
/0 
} 20 
2 =n 40 
Increase | go 
60 
FEMA..E. NONIMMIGRANT 
14151161718 19 [20| 21 [22 | 23]24 
Years Ending June 30 
sNumerical’data in Table 36. 
All of the curves shown in the above chart have been plotted to the same ratio 
scale, so that equal vertical distances measured upward indicate the same percentage 
increase; and equal distances measured downward, the same percentage decrease, as 
shown by the Scales of Percentage Change accompanying the chart. But, to avoid 
confusing recrossing, each curve has a different base line; hence in interpreting this 
chart only the slope, or vertical change, and not the vertical position of a curve, should 
be considered. 
Method of Charting. 
The method of charting used in Chart 27 may not be familiar to 
the reader, and as there are several charts in this and the following 
chapter which are similar in principle a few words of explanation 
are pertinent. These are so-called “ratio” or ‘rate-of-change” 
charts, with a logarithmic vertical scale and also with a different