0% (1978)

20% (2006)

20% (1997)

20% (2000)

40% (1998)

20% (1976)

0% (1973)

20% (1979)

20% (1999)

0% (1986)

20% (1981)

20% (2002)

20% (1990)

50% (2000)

40% (2012)

20% (1999)

50% (1986)

35% (1980)

45% (1985)

20% (1989)