55% (1987)

60% (1976)

64% (1980)

45% (1978)

57% (1975)

54% (1981)

51% (1979)

65% (1970)

60% (1978)

54% (1980)

47% (1977)

51% (1978)

55% (1982)

59% (1975)

53% (1980)

49% (1979)

53% (1988)

71% (1973)

60% (1980)

47% (1983)