1990

7.7

2003

7.5

1994

8.5

2007

6.9

2004

7.1

1975

8.4

1997

8.4

2006

7.7

2004

8.1

2007

7.2

2002

6.8

1997

6.5

1991

7.4

1977

4.7

2017

6.0

2017

8.1

1977

8.0

1991

4.2

2011

7.2

2015

6.0