1974

6.4

1995

5.7

1988

7.4

2007

4.9

2009

5.5

1989

6.1

2003

5.9

2001

4.3

1970

6.4

1990

5.9

1994

6.0

1992

5.6

1988

5.8

2006

6.8

2007

5.9

1997

6.0

2002

6.9

2013

5.9

1977

7.9

2022

7.1