1991

7.1

1998

7.8

1998

6.9

2003

8.0

2011

5.2

2012

7.4

1995

8.4

1972

8.7

2008

6.3

2017

7.3

1999

7.6

1968

8.1

2011

8.3

2012

7.1

2015

7.7

2008

6.5

1964

7.5

2006

7.4

1966

8.5

2016

6.3