60% (1981)

62% (1985)

60% (1988)

51% (2005)

64% (1999)

65% (1978)

51% (1994)

62% (1992)

57% (2002)

49% (2008)

55% (1990)

48% (1963)

61% (1986)

51% (1962)

52% (1973)

43% (1961)

66% (1980)

50% (1995)

60% (1977)

65% (1983)