52% (2000)

62% (1996)

70% (1997)

57% (1994)

65% (1990)

56% (1991)

53% (1993)

61% (1992)

57% (2000)

47% (2001)

62% (1994)

48% (1991)

63% (1990)

54% (1992)

66% (1997)

54% (1996)

55% (1996)

57% (1991)

51% (1994)

53% (1996)