73% (1976)

65% (1995)

61% (1997)

44% (2001)

65% (1999)

61% (1998)

49% (2003)

45% (2002)

59% (1990)

49% (1995)

58% (2000)

57% (1993)

52% (1992)

58% (1993)

69% (1990)

52% (1988)

61% (1999)

62% (1996)

55% (1989)

40% (1991)