66% (1976)

72% (1971)

68% (1970)

58% (1975)

59% (1972)

68% (1974)

57% (1974)

62% (1973)

51% (1973)

57% (1975)

70% (1972)

60% (1975)

72% (1975)

0% (1973)

52% (2005)

60% (2010)