1990

6.1

2001

7.0

1975

6.8

1949

5.1

1980

6.8

2005

5.2

1995

4.6

2011

7.6

1996

6.9

1948

7.4

1968

7.1

1962

6.9

2001

7.2

1980

7.0

1972

5.9

2003

7.3

2001

6.1

1998

6.2

2017

5.6