2015

6.1

1962

7.8

2016

6.1

2017

6.3

2017

6.6

2005

5.2

1991

6.2

2007

6.1

2013

6.6

1986

5.6

2011

6.8

1966

6.2

1975

7.8

1988

6.3

1964

8.1

1968

8.1

1974

6.6

2012

7.1

1996

7.6

1978

6.0