| メス | オス | 合計 | 性比(♂割合) | ||
| 1985 | 0 | 1 | 1 | 1 | |
| 1986 | 0 | 0 | 0 | ||
| 1987 | 2 | 4 | 6 | 0.666667 | |
| 1988 | 2 | 1 | 3 | 0.333333 | |
| 1989 | 2 | 2 | 4 | 0.5 | |
| 1990 | 1 | 4 | 5 | 0.8 | |
| 1991 | 2 | 2 | 4 | 0.5 | |
| 1992 | 2 | 3 | 5 | 0.6 | |
| 1993 | 1 | 1 | 2 | 0.5 | |
| 1994 | 2 | 2 | 4 | 0.5 | |
| 1995 | 4 | 4 | 8 | 0.5 | |
| 1996 | 5 | 3 | 8 | 0.375 | |
| 1997 | 2 | 4 | 6 | 0.666667 | |
| 1998 | 8 | 3 | 11 | 0.272727 | |
| 1999 | 0 | 0 | |||
| 2000 | 2 | 2 | 2 | ||
| 2001 | 1 | 1 | 1 | ||
| 2002 | 1 | 1 | 1 | ||
| 2003 | 4 | 4 | 4 | ||
| 2004 | 4 | 4 | 4 | ||
| 2005 | 2 | 2 | 2 | ||
| 平均 | 1.116547 | ||||