2015

6.1

2007

6.5

1982

5.9

1994

5.3

1993

4.6

1973

5.7

1986

6.3

1990

6.3

1984

7.3

2004

6.1

1999

5.6

1985

6.5

1985

5.3

1949

6.9

1981

6.7

2011

4.8

2012

6.0

1989

7.1

1994

7.2

1993

6.4