57% (1975)

41% (1971)

45% (1991)

51% (1969)

72% (1977)

59% (1988)

48% (1989)

80% (1979)

60% (1984)

68% (1974)

35% (1968)

75% (1981)

47% (1996)

48% (1970)

58% (1990)

59% (1976)

54% (1987)

54% (1970)

40% (1990)

56% (1994)