79% (1982)

75% (1978)

73% (1974)

69% (1980)

67% (1978)

67% (1966)

61% (1984)

68% (1967)

67% (1969)

60% (1976)

56% (1976)

59% (1974)

57% (1977)

69% (1994)

62% (1972)

68% (1971)

69% (1984)

63% (1986)

68% (1982)

51% (2015)