1999

5.1

2006

6.8

1986

6.2

2003

6.3

1968

6.6

2005

6.9

1988

6.1

1988

5.7

1996

6.5

1997

6.1

1964

7.4

1980

6.7

1983

6.5

1996

7.5

1993

5.8

2003

5.8

1980

6.6

2014

5.7

1988

6.9

2014

5.5