| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 16.74 | 24 |
| 2015 | 14.89 | 40 |
| 2014 | 15.61 | 30 |
| 2013 | 14.85 | 48 |
| 2012 | 17.01 | 36 |
| 2011 | 16.92 | 45 |
| 2010 | 21.08 | 40 |
| 2009 | 20.24 | 36 |
| 2008 | 16.41 | 70 |
| 2007 | 13.55 | 109 |
| 2006 | 20.22 | 72 |
| 2005 | 15.81 | 76 |
| 2004 | 14.13 | 78 |
| 2003 | 14.07 | 75 |
| 2002 | 14.5 | 67 |
| 2001 | 43 | 23 |
| 2000 | 19.35 | 51 |
| 1999 | 15.47 | 68 |
| 1998 | 11.41 | 77 |
| 1997 | 9.74 | 105 |
| 1996 | 10.73 | 96 |
| 1995 | 12.15 | 89 |
| 1994 | 19.33 | 75 |
| 1993 | 10.51 | 86 |
| 1992 | 12.04 | 85 |
| 1991 | 13.71 | 77 |
| 1990 | 10.4 | 79 |
| 1989 | 18.64 | 55 |
| 1988 | 13.66 | 76 |
| 1987 | 18.81 | 52 |
| 1986 | 16.26 | 55 |