47% (1977)

51% (1978)

54% (1988)

71% (1973)

55% (1982)

69% (1977)

54% (1981)

66% (1974)

63% (1968)

51% (1979)

52% (1979)

75% (1974)

53% (1980)

53% (1979)

64% (1980)

53% (2009)

75% (1975)

54% (1986)

65% (2002)

60% (1978)