1992

6.7

1993

6.1

1968

8.0

2002

10.0

2009

9.7

2017

8.2

2014

9.0

2011

7.0

2002

6.3

2005

6.9

1987

6.6

2017

7.4

1987

6.7

2001

6.0

2002

5.9

2006

5.0

1997

6.4

1999

5.7

1977

6.2

1993

6.9