57% (1980)

54% (1973)

56% (1975)

53% (1975)

51% (1991)

54% (1980)

40% (1983)

54% (1984)

62% (1975)

58% (1976)

39% (1976)

33% (1976)

58% (1974)

50% (1976)

51% (1976)

52% (1980)

48% (1980)

61% (1997)

20% (2002)

48% (1980)