1999

5.5

2006

5.6

2005

4.2

1991

6.5

1986

6.8

1994

6.2

1976

7.3

1995

6.3

1985

6.5

2004

5.7

2006

6.1

1999

6.0

2001

7.1

1968

6.9

2017

6.3

2007

6.1

1991

6.2

1990

6.7

1993

5.5

1982

6.0