1968

5.0

1995

7.3

2006

5.8

1989

6.7

1997

6.7

1958

7.4

1988

7.5

1998

6.1

1998

6.5

1992

6.9

2006

6.6

1980

6.2

1994

5.2

2017

6.6

1988

5.5

1996

5.6

2000

6.1

1999

6.4

2009

5.7

1975

6.6