1998

7.1

2000

5.9

2007

6.4

1993

5.7

1974

5.0

1990

7.0

1997

7.3

2005

6.8

1964

7.2

1975

6.9

2002

6.1

1975

4.9

1962

7.9

1995

6.9

1941

3.5

2008

5.1

1983

6.7

2016

8.0

1987

6.6

2008

6.7