65% (1999)

70% (2001)

72% (2004)

70% (2005)

71% (1992)

73% (1992)

68% (1986)

43% (2003)

63% (1997)

62% (1988)

65% (1989)

57% (1990)

56% (1996)

55% (2008)

56% (1991)

61% (2009)

63% (1988)

61% (1990)

42% (1986)

46% (2008)