1979

7.7

1977

7.7

1973

7.4

1996

7.3

1953

7.3

2007

6.3

1998

7.7

2007

6.9

2007

6.1

2006

6.3

2003

5.8

2007

4.4

1991

6.2

1990

6.7

2001

7.1

2003

6.4

2015

7.2

2005

7.0

2001

7.8

2004

7.3