52% (1974)

70% (1996)

56% (2004)

56% (2011)

65% (1985)

68% (1986)

65% (1994)

88% (2005)

98% (1995)

61% (1990)

56% (2006)

50% (1989)

49% (1977)

65% (1989)

58% (1983)

41% (1971)

57% (2004)

48% (1994)

53% (1986)

60% (1990)