1968

6.4

1993

6.2

1988

6.7

1993

7.6

1999

4.6

2002

7.0

1994

6.8

2001

6.0

1990

6.5

1994

6.1

1968

7.5

1991

6.3

2004

3.7

1998

5.8

1953

5.0

2006

5.5

1991

5.4

2019

6.7

1974

7.2

1963

6.7