70% (2008)

54% (2005)

70% (2006)

70% (2007)

76% (2007)

60% (2004)

62% (2005)

50% (2006)

69% (2007)

47% (2003)

62% (2001)

36% (2004)

60% (1978)

57% (1980)

52% (2005)

35% (1969)

37% (2003)

30% (2005)