| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 5.29 | 13 |
| 2015 | 4.65 | 21 |
| 2014 | 3.84 | 22 |
| 2013 | 3.89 | 48 |
| 2012 | 4.88 | 35 |
| 2011 | 3.87 | 47 |
| 2010 | 1.69 | 92 |
| 2009 | 0.7 | 58 |
| 2008 | 2.01 | 80 |
| 2007 | 2.87 | 87 |
| 2006 | 2.36 | 83 |
| 2005 | 2.49 | 96 |
| 2004 | 3.91 | 67 |
| 2003 | 3.36 | 57 |
| 2002 | 2.93 | 57 |
| 2001 | 1.9 | 67 |
| 2000 | 2.96 | 52 |
| 1999 | 1.79 | 70 |
| 1998 | 1.19 | 94 |
| 1997 | 2.66 | 62 |
| 1996 | 2.27 | 75 |
| 1995 | 1.43 | 66 |
| 1994 | 1.31 | 66 |
| 1993 | 0.61 | 67 |
| 1992 | 0.77 | 58 |
| 1991 | -.25 | 68 |
| 1990 | 2.73 | 32 |
| 1989 | 2.32 | 43 |
| 1988 | 3.46 | 35 |
| 1987 | 1.3 | 51 |
| 1986 | 0.58 | 56 |