57% (1975)

51% (1965)

61% (1972)

71% (1977)

58% (1990)

48% (1989)

58% (1988)

48% (1969)

54% (1987)

41% (1971)

46% (1991)

68% (1974)

70% (1969)

52% (1970)

40% (1991)

30% (1986)

30% (1980)

48% (1970)

50% (1962)

0% (1992)