67% (1982)

61% (1979)

51% (1981)

56% (1976)

64% (1977)

62% (1977)

60% (1978)

70% (1976)

68% (1974)

62% (1976)

65% (1976)

68% (1975)

54% (1979)

61% (1982)

52% (1983)

54% (1978)

45% (1981)

45% (1974)

40% (1983)

57% (1979)