1992

7.4

1997

6.5

2004

1.0

1975

4.0

2001

6.4

1970

3.9

1973

5.8

2014

4.7

2003

7.1

1975

5.2

1994

5.8

1998

5.1

1974

5.8

2010

8.1

1998

6.4

2016

6.0

2005

6.2

1963

7.2

1976

5.7

1986

4.7