Number of Births.
| Year. | Total Births in California. | Japanese Births in California. | Japanese Births— Percentage of Total. |
| 1906 | ..... | 134 | ..... |
| 1907 | ..... | 221 | ..... |
| 1908 | ..... | 455 | ..... |
| 1909 | ..... | 682 | ..... |
| 1910 | 32,138 | 719 | 2.24% |
| 1911 | 34,828 | 995 | 2.86% |
| 1912 | 39,330 | 1,407 | 3.73% |
| 1913 | 43,852 | 2,215 | 5.05% |
| 1914 | 46,012 | 2,874 | 6.25% |
| 1915 | 48,075 | 3,342 | 6.95% |
| 1916 | 50,638 | 3,721 | 7.35% |
| 1917 | 52,230 | 4,108 | 7.87% |
| 1918 | 55,922 | 4,218 | 7.54% |
| 1919 | 56,527 | 4,378 | 7.75% |
| Totals | 459,552 | 29,469 |
The table indicates in the first place that the birth rate of California as a whole is steadily growing, and in the second place that the birth rate of the Japanese was very low until 1906 or 1907, but since then it has been rapidly growing. The relative percentage of Japanese births in the total births of California, however, indicates the tendency to diminish, having reached the highest mark in 1917, when it was 7.87 per cent., but decreasing slightly in the last few years.
The exceedingly high birth rate of the Japanese in California becomes clearer when considered in terms of the rate of birth per thousand of population. In the year 1919, the number of births in California was 1.79 per thousand population. In Japan, where the birth rate is high, it was 2.53 during the past decade. The birth rate of Japanese in California is more than three times as high as that for the total of California, and more than double that in Japan.
There are several reasons for this abnormally high birth rate among the Japanese in California. In the first place, a large portion of these Japanese are in the prime of life, and moreover they are selected groups of vigorous and healthy individuals. Commenting on the age distribution of Japanese in this country, the report of the Bureau of Census states[22]:
The most noteworthy fact about the age distribution of the Japanese is their remarkable concentration on the age groups 25 to 44, nearly two-thirds of the Japanese being in this period of life. Only 4.5 per cent. of the Japanese are over 45 years of age, as compared with 44.7 per cent. of the Chinese. The explanation is, doubtless, to be found in the fact that the Japanese represent more recent immigration than the Chinese.
The truth of this statement was borne out by the recent investigation conducted by the Japanese Association of San Francisco, which obtained the following result in thirty-six northern counties of California:
Age Distribution of Japanese in Middle and Northern California, 1920.
| Age. | Male. | Female. | Total. | Percentage of Age Group. |
| Under 7 | 4,078 | 3,786 | 7,864 | 18.% |
| 8 to 16 | 2,035 | 1,663 | 3,698 | 8.% |
| 17 to 40 | 17,037 | 8,535 | 25,572 | 59.% |
| Above 40 | 5,683 | 805 | 6,488 | 15.% |
| Total | 28,833 | 14,789 | 43,622 | 100. |
Thus, out of the total number of 43,622 investigated, 25,572 or nearly 59 per cent. are between the ages of seventeen to forty, only 5 per cent. of females being those who passed the age of fertility.