68% (1986)

70% (2001)

65% (1999)

70% (2005)

63% (1997)

62% (1988)

72% (2004)

60% (1990)

56% (1991)

70% (1992)

57% (1996)

72% (1992)

64% (1989)

64% (1988)

55% (2008)

57% (1990)

53% (2003)

43% (1986)

46% (2008)

61% (2009)