1993

4.7

1984

3.0

1990

3.5

2001

5.8

1990

6.3

2006

6.6

2005

5.3

2001

4.9

2008

4.5

1974

6.9

2002

6.6

2000

6.0

2002

6.1

1988

7.1

2002

3.8

2008

4.2

2006

4.1

2015

6.3

1973

7.3

1995

4.1