58% (1980)

40% (1983)

51% (1991)

48% (1980)

54% (1973)

39% (1976)

62% (1975)

48% (1980)

53% (1975)

58% (1976)

50% (1979)

61% (1997)

40% (1980)

52% (1980)

38% (1974)

56% (1975)

51% (1976)

54% (1980)

20% (2002)

71% (2003)