1976

4.8

2011

5.9

1996

5.8

2004

5.7

2018

7.1

1982

7.6

2013

8.4

2000

7.4

2001

6.8

1988

5.4

2022

6.7

2002

6.0

1977

4.5

2017

6.3

1995

7.9

1989

4.9

1957

7.2

2012

5.0

1994

6.0

1975

6.9