48% (1977)

53% (1979)

53% (1980)

54% (1981)

54% (1982)

56% (1975)

65% (1980)

52% (1979)

75% (1974)

55% (1980)

58% (1978)

63% (1968)

53% (1988)

54% (2009)

57% (1981)

46% (1978)

60% (1976)

69% (1977)

52% (1978)

65% (2002)