1970

7.4

2005

6.7

1999

7.7

2006

6.0

2002

6.3

2000

7.4

2007

6.5

1996

6.9

2002

5.9

2004

7.5

2016

6.2

1998

6.6

2016

5.7

1993

7.7

2005

6.6

2007

7.6

1959

7.7

2008

4.0

1994

8.3

1989

8.0