1980

4.3

1973

7.0

1991

5.1

2015

5.7

1992

3.3

2003

4.0

2000

4.2

1997

6.6

1932

4.0

1932

6.0

1985

6.7

1986

5.5

1968

7.5

1992

6.7

1986

6.1

2002

5.8

2005

5.9

2005

6.1

1998

6.3

2005

5.0