53% (2007)

54% (2004)

20% (2011)

20% (2000)

60% (2012)

71% (2007)

54% (2008)

61% (2005)

20% (1991)

20% (1979)

35% (2009)

62% (1985)

30% (1991)

56% (1978)

52% (2011)

53% (1970)

69% (1998)

25% (2001)

58% (1991)

20% (1986)