81% (1992)

70% (1994)

63% (1992)

60% (1996)

69% (1996)

60% (1997)

62% (1993)

65% (1992)

66% (1992)

62% (1993)

66% (1997)

62% (1996)

48% (1994)

43% (1994)

64% (1994)

64% (1997)

46% (1989)

42% (1993)

48% (1995)

52% (1998)