1990

7.4

1968

6.9

1984

6.6

1986

6.8

1996

7.3

1995

5.6

1997

6.2

2006

5.5

1998

6.4

2005

6.6

1982

7.4

1989

5.7

1991

7.0

1980

8.4

2016

7.5

1963

6.9

1973

6.9

2008

6.2

1993

6.7

1993

6.4