1951

7.2

2005

6.4

1961

7.2

2002

6.3

1980

6.2

2010

5.9

1989

7.4

1984

7.3

1992

5.3

1990

6.1

1986

6.3

2000

8.0

1993

7.5

2003

4.9

2002

5.2

1983

6.5

1987

7.9

1999

6.2

1986

6.7

2007

4.9