76% (1987)

58% (1996)

74% (1993)

70% (1992)

50% (2003)

57% (2009)

57% (1988)

60% (2000)

62% (2005)

59% (1995)

65% (1965)

58% (1981)

60% (1990)

49% (2007)

55% (1979)

51% (1975)

51% (1995)

61% (1983)

55% (1984)

57% (1991)