1992

6.2

2002

2.0

1961

7.7

1994

7.0

2005

6.8

2006

7.1

1999

7.8

2003

7.2

2002

4.5

1999

6.8

1994

5.8

1993

5.0

1997

6.9

1995

6.7

1968

6.8

1989

7.8

1975

7.8

2002

7.2

1943

7.7

1992

3.0