62% (1981)

55% (1990)

50% (1995)

61% (1985)

61% (1988)

67% (1964)

64% (1999)

63% (1992)

66% (1980)

51% (2005)

61% (1986)

51% (1994)

49% (1963)

57% (2002)

65% (1978)

51% (1962)

49% (2008)

43% (1961)

65% (1983)

60% (1977)