1977

6.8

1985

6.2

1984

7.2

1987

6.5

1982

6.7

1999

7.0

1991

7.2

2006

6.0

1989

0.0

2000

6.5

2001

6.9

2015

6.0

1988

7.8

1997

7.2

2002

6.4

2005

7.1

1994

6.2

1959

8.0

1973

6.5

1994

5.9