72% (1991)

65% (1997)

60% (1994)

63% (1998)

58% (1994)

63% (1992)

63% (1996)

61% (1996)

64% (1997)

65% (1993)

56% (1997)

59% (1991)

55% (1992)

68% (1996)

56% (1999)

48% (1997)

55% (1992)

46% (1996)

44% (1996)

54% (1997)