| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 15.5 | 23 |
| 2015 | 13.25 | 39 |
| 2014 | 11.573 | 53 |
| 2013 | 9.521 | 73 |
| 2012 | 12.15 | 54 |
| 2011 | 18.837 | 14 |
| 2010 | 20.916 | 13 |
| 2009 | 22.063 | 11 |
| 2008 | 19.063 | 23 |
| 2007 | 18.889 | 21 |
| 2006 | 23.153 | 16 |
| 2005 | 28.209 | 9 |
| 2004 | 30.727 | 10 |
| 2003 | 40.571 | 8 |
| 2002 | 45.198 | 6 |
| 2001 | 46.233 | 6 |
| 2000 | 38.8 | 11 |
| 1999 | 40.517 | 13 |
| 1998 | 31.8 | 23 |
| 1997 | 46.692 | 14 |
| 1996 | 53.783 | 14 |
| 1995 | 45.533 | 16 |
| 1994 | 70.558 | 8 |
| 1993 | 113.308 | 4 |
| 1992 | 54.567 | 8 |
| 1990 | 35.104 | 12 |
| 1989 | 18.39 | 30 |
| 1988 | 18.39 | 21 |
| 1987 | 21.196 | 17 |
| 1986 | 27.395 | 7 |