63% (2005)

74% (1993)

71% (1992)

77% (1987)

50% (2003)

64% (1998)

62% (1983)

51% (2001)

58% (2009)

52% (1995)

60% (2000)

58% (1996)

61% (1990)

54% (1988)

66% (2005)

55% (1984)

58% (1981)

54% (1979)

49% (1975)

57% (1964)