63% (1990)

62% (1989)

58% (2006)

59% (2011)

50% (1984)

44% (1988)

54% (1991)

48% (1994)

59% (1989)

64% (1987)

58% (1986)

50% (1993)

55% (1996)

55% (2001)

65% (1986)

54% (1987)

66% (1985)

57% (1987)

64% (1988)

51% (2007)