50% (1977)

54% (1992)

59% (1973)

53% (1979)

52% (1976)

54% (1981)

48% (1993)

48% (1975)

53% (1988)

52% (1979)

55% (1982)

64% (1980)

68% (2004)

55% (1980)

54% (1986)

53% (1980)

53% (1977)

60% (1975)

56% (1980)

57% (1981)