1968

7.2

1985

8.3

1994

8.7

2008

8.5

1972

8.7

1997

7.9

1994

8.5

2013

8.1

2007

7.3

1984

7.7

1977

8.2

2006

7.5

2019

8.1

2009

7.3

2009

7.6

2018

7.4

1994

8.5

2001

7.4

1990

7.4

2019

8.5