70% (1971)

52% (1978)

53% (1999)

42% (1974)

47% (1975)

57% (1983)

55% (1983)

57% (2007)

52% (1972)

57% (2001)

63% (1997)

55% (1998)

67% (1977)

63% (1983)

61% (1973)

55% (1997)

74% (1983)

57% (1972)

62% (1978)

58% (1988)