61% (2009)

71% (1986)

71% (1981)

63% (1980)

61% (2013)

70% (1984)

72% (1989)

71% (1992)

66% (1996)

65% (1995)

70% (1999)

64% (2002)

56% (1991)

62% (1999)

55% (1987)

60% (1980)

55% (1977)

68% (2003)

71% (1990)

61% (1997)