1987

6.0

1982

7.1

2001

6.8

1998

7.5

2002

7.1

1995

7.7

2005

8.1

1995

7.1

1999

7.6

1993

8.1

2006

0.0

1980

5.5

1967

6.4

2006

5.0

1972

6.8

1975

8.3

1984

7.8

2019

7.0

2017

0.0

2019

6.9