| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 11.81 | 41 |
| 2015 | 10.8 | 62 |
| 2014 | 13.86 | 45 |
| 2013 | 7.55 | 104 |
| 2012 | 15.4 | 44 |
| 2011 | 16.51 | 47 |
| 2010 | 16.92 | 53 |
| 2009 | 16.75 | 55 |
| 2008 | 18.79 | 55 |
| 2007 | 22.06 | 59 |
| 2006 | 18.65 | 80 |
| 2005 | 18.71 | 57 |
| 2004 | 14.64 | 76 |
| 2003 | 17.58 | 55 |
| 2002 | 6.63 | 113 |
| 2001 | 37.88 | 28 |
| 2000 | 19.7 | 49 |
| 1999 | 18.12 | 56 |
| 1998 | 12.02 | 72 |
| 1997 | 17.24 | 75 |
| 1996 | 31.03 | 32 |
| 1995 | 44.3 | 20 |
| 1994 | 1102.38 | 3 |
| 1993 | 3280.65 | 1 |
| 1992 | 1749.38 | 2 |
| 1991 | 501.62 | 3 |
| 1990 | 640.87 | 4 |
| 1989 | 1904.89 | 4 |
| 1988 | 2732.95 | 2 |
| 1987 | 213.67 | 3 |
| 1986 | 289.21 | 1 |