Total babies named Koichi (all years): 145
| Year | Boys (count / rank / %) |
|---|---|
| 2007 | 5 / #13508 / 0.000% |
| 1994 | 5 / #9626 / 0.000% |
| 1988 | 6 / #6883 / 0.000% |
| 1930 | 6 / #3815 / 0.001% |
| 1929 | 5 / #4296 / 0.000% |
| 1927 | 8 / #3311 / 0.001% |
| 1926 | 6 / #3977 / 0.001% |
| 1925 | 6 / #3975 / 0.001% |
| 1924 | 11 / #2749 / 0.001% |
| 1923 | 12 / #2532 / 0.001% |
| Year | Boys (count / rank / %) |
|---|---|
| 1922 | 9 / #3137 / 0.001% |
| 1921 | 16 / #2111 / 0.001% |
| 1920 | 8 / #3363 / 0.001% |
| 1919 | 12 / #2435 / 0.001% |
| 1918 | 12 / #2470 / 0.001% |
| 1917 | 8 / #3070 / 0.001% |
| 1916 | 5 / #4230 / 0.001% |
| 1914 | 5 / #3523 / 0.001% |