41% (1971)

72% (1977)

57% (1975)

45% (1991)

48% (1989)

59% (1988)

51% (1969)

30% (1980)

58% (1990)

47% (1996)

60% (1984)

68% (1974)

75% (1981)

54% (1987)

35% (1968)

60% (1993)

61% (1972)

59% (1976)

40% (1990)

40% (1991)