57% (1980)

47% (1991)

48% (1980)

46% (1977)

55% (1973)

0% (1977)

50% (1979)

56% (1975)

51% (1976)

50% (1983)

41% (1983)

40% (1976)

42% (1974)

48% (1980)

50% (1976)

54% (1980)

55% (1984)

53% (1975)

61% (1997)

71% (2003)