1964

6.2

2001

6.8

2005

5.6

1986

5.7

1953

6.9

2006

3.0

2003

6.0

1998

6.8

1964

5.2

1968

5.8

2015

3.1

2005

5.9

2004

7.2

1980

7.7

1940

5.0

2006

7.0

1967

7.7

1990

6.9

1999

7.0

2004

6.8