58% (2003)

49% (2007)

54% (2008)

51% (1997)

62% (1997)

64% (2001)

59% (2009)

58% (2005)

44% (2011)

60% (1998)

70% (2002)

54% (1996)

53% (2004)

55% (1996)

54% (2010)

40% (1991)

48% (1995)

61% (1998)

49% (1994)

40% (2009)