| value | category | cases | |
|---|---|---|---|
| 1973 | 1 |
0.2%
|
|
| 1978 | 2 |
0.3%
|
|
| 1979 | 2 |
0.3%
|
|
| 1980 | 9 |
1.5%
|
|
| 1981 | 4 |
0.7%
|
|
| 1982 | 4 |
0.7%
|
|
| 1983 | 11 |
1.9%
|
|
| 1984 | 14 |
2.4%
|
|
| 1985 | 23 |
3.9%
|
|
| 1986 | 15 |
2.5%
|
|
| 1987 | 22 |
3.7%
|
|
| 1988 | 27 |
4.6%
|
|
| 1989 | 18 |
3%
|
|
| 1990 | 32 |
5.4%
|
|
| 1991 | 37 |
6.3%
|
|
| 1992 | 35 |
5.9%
|
|
| 1993 | 53 |
9%
|
|
| 1994 | 63 |
10.7%
|
|
| 1995 | 61 |
10.3%
|
|
| 1996 | 73 |
12.4%
|
|
| 1997 | 85 |
14.4%
|
|
| 9997 | Inconsistent | 0 |
0%
|
| 9998 | Don't know | 0 |
0%
|
| Sysmiss | 10054 |