1989

5.5

1991

6.2

1995

5.6

2004

6.8

1959

6.1

1994

6.2

1988

6.4

1996

5.8

2009

4.7

2001

6.4

1989

6.2

1995

4.6

1987

5.2

1995

6.2

1984

6.6

1998

6.0

1952

6.7

1986

5.8

2003

7.3

2011

5.7