1959

0.0

1991

6.4

1976

7.0

1982

7.3

1992

6.7

1966

6.6

1968

7.4

1977

6.8

1986

7.9

1982

5.1

1989

7.9

1993

5.8

2005

7.0

1966

7.4

2001

6.7

1998

7.8

1984

6.1

1969

5.5

1998

7.1

1997

6.8