1991

7.9

2002

6.5

1997

7.3

1969

6.7

1998

7.1

2000

7.6

2004

7.7

1971

7.8

2000

8.5

1983

7.5

2004

8.4

2018

9.0

2013

5.8

2013

6.2

2005

6.7

1964

8.0

2004

6.6

2001

6.5

2007

4.0

2009

5.7