1986

7.6

1988

5.9

1993

6.1

2000

4.3

1957

7.2

2004

6.8

1986

7.6

2004

6.7

1968

6.9

1981

6.2

2013

8.1

2001

6.2

1988

7.8

1972

7.9

1999

8.0

1999

6.6

1994

7.4

1973

7.0

1979

7.3

1981

7.0