| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 18.075 | 12 |
| 2015 | 19.736 | 12 |
| 2014 | 21.186 | 10 |
| 2013 | 19.271 | 13 |
| 2012 | 17.158 | 23 |
| 2011 | 17.398 | 19 |
| 2010 | 26.036 | 5 |
| 2009 | 28.257 | 4 |
| 2008 | 25.808 | 5 |
| 2007 | 25.025 | 9 |
| 2006 | 30.143 | 5 |
| 2005 | 29.91 | 8 |
| 2004 | 33.544 | 7 |
| 2003 | 49.99 | 5 |
| 2002 | 38.655 | 7 |
| 2001 | 28.253 | 16 |
| 2000 | 26.782 | 23 |
| 1999 | 30.208 | 22 |
| 1998 | 30.488 | 27 |
| 1997 | 27.787 | 28 |
| 1996 | 31.883 | 28 |
| 1995 | 33.944 | 26 |
| 1994 | 35.468 | 21 |
| 1993 | 30.777 | 25 |
| 1992 | 27.957 | 22 |
| 1991 | 34.937 | 16 |
| 1990 | 31 | 15 |