1991

7.3

1995

7.2

2001

7.0

2016

5.5

2006

7.9

2002

6.6

2004

6.4

2005

6.7

2016

6.5

1927

8.1

1968

8.1

1995

7.6

1985

7.7

2005

6.5

1982

7.9

1982

6.6

1988

7.9

1971

8.2

1984

7.7

2009

6.1