1994

5.6

1997

5.2

1991

4.2

2015

6.5

2007

7.9

1997

6.7

1986

7.0

2011

7.1

2005

7.7

1990

5.3

1986

4.6

1994

6.1

1998

6.9

1993

8.4

2008

7.6

1998

5.2

1994

4.8

1999

5.5