1979

7.1

1989

5.8

1949

7.5

1968

7.6

1999

6.6

2015

5.6

2020

6.9

1988

5.6

1966

6.1

1956

6.6

2006

7.3

2001

7.0

1960

8.1

2017

8.4

2006

6.6

1960

6.2

1976

6.5

1960

7.7

1971

6.8

1970

7.6