69% (1981)

20% (1980)

80% (1997)

52% (1997)

27% (1996)

60% (1995)

52% (1984)

40% (1987)

74% (1992)

55% (1984)

40% (1988)

57% (1996)

48% (1982)

0% (1978)

45% (1982)

70% (1989)

30% (1990)