1990

6.3

2002

5.8

1992

7.5

2001

7.3

2012

7.8

2000

5.4

1971

7.0

2013

5.8

1987

5.5

1984

6.5

1999

6.2

1954

8.0

1997

6.6

2015

5.2

1989

7.1

1989

7.0

2010

5.4

1993

6.7

1986

6.8

2005

7.4