67% (1986)

68% (1988)

60% (2008)

58% (1990)

72% (1996)

64% (1981)

66% (1999)

68% (1983)

47% (1993)

35% (2006)

64% (1991)

52% (1985)

42% (1957)

44% (1992)

62% (1992)

45% (1993)

58% (1997)

55% (1986)

43% (1998)

57% (1986)