2001

7.6

2018

7.3

1996

6.8

1995

7.8

2015

8.4

2007

7.6

1993

7.9

1987

8.4

2009

7.9

2007

7.7

1980

8.6

1998

6.9

1994

8.4

1984

6.9

2002

6.4

2002

6.7

2011

6.1

1962

7.2

1990

6.9

2015

8.0