| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 5.4 | 13 |
| 2015 | 4.43 | 21 |
| 2014 | 3.46 | 52 |
| 2013 | 3.92 | 45 |
| 2012 | 1.09 | 119 |
| 2011 | 1.55 | 128 |
| 2010 | -.21 | 160 |
| 2009 | -6.29 | 177 |
| 2008 | 10.28 | 5 |
| 2007 | 8.45 | 30 |
| 2006 | 8.7 | 21 |
| 2005 | 4.82 | 62 |
| 2004 | 8.98 | 19 |
| 2003 | 6.29 | 35 |
| 2002 | 7.13 | 17 |
| 2001 | 7.08 | 17 |
| 2000 | 2.53 | 114 |
| 1999 | -.25 | 139 |
| 1998 | -1.88 | 169 |
| 1997 | -4.54 | 184 |
| 1996 | 4.17 | 62 |
| 1995 | 7.36 | 18 |
| 1994 | 4.08 | 47 |
| 1993 | 1.67 | 76 |
| 1992 | -7.94 | 154 |
| 1991 | -12.16 | 171 |