1961

7.2

1990

6.1

2001

6.1

1980

6.1

2010

7.8

2000

5.5

2014

6.0

2003

7.1

1959

8.1

2007

6.0

2007

6.7

1980

7.3

2001

5.9

1998

6.8

2003

7.8

1947

7.3

1994

7.4

1986

7.6

2005

6.1