65% (1983)

61% (1985)

67% (1980)

53% (1987)

47% (1991)

62% (1993)

61% (1988)

57% (1991)

56% (1983)

59% (1989)

55% (1987)

58% (1985)

58% (1986)

60% (1990)

67% (1981)

69% (1988)

58% (1993)

48% (1992)

58% (1990)

44% (1988)