73% (1974)

72% (1993)

55% (2008)

65% (1982)

74% (1991)

67% (1980)

68% (1986)

66% (1985)

58% (1996)

71% (1981)

73% (1967)

47% (1975)

61% (1986)

73% (1973)

71% (1982)

62% (1980)

62% (1995)

65% (1978)

51% (2007)

70% (1976)