51% (1981)

67% (1982)

61% (1978)

62% (1976)

70% (1976)

55% (1976)

64% (1977)

68% (1974)

67% (1975)

66% (1976)

61% (1979)

65% (1977)

54% (1978)

45% (1974)

52% (1983)

57% (1979)

61% (1982)

54% (1979)

45% (1981)

40% (1983)