| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 3.82 | 24 |
| 2015 | 6.31 | 8 |
| 2014 | 7.29 | 4 |
| 2013 | 3.54 | 52 |
| 2012 | 1.8 | 89 |
| 2011 | 0.97 | 138 |
| 2010 | 3.04 | 92 |
| 2009 | -3.19 | 130 |
| 2008 | 2.68 | 91 |
| 2007 | 3.62 | 110 |
| 2006 | 1.46 | 162 |
| 2005 | 3.12 | 100 |
| 2004 | -.23 | 179 |
| 2003 | 1.87 | 121 |
| 2002 | 2.22 | 80 |
| 2001 | -.14 | 148 |
| 2000 | 6.08 | 35 |
| 1999 | 4.1 | 46 |
| 1998 | 4.44 | 44 |
| 1997 | 4.46 | 55 |
| 1996 | 3.1 | 84 |
| 1995 | 5.6 | 31 |
| 1994 | 4.67 | 40 |
| 1993 | 3.44 | 45 |
| 1992 | 3.62 | 45 |
| 1991 | 3.43 | 37 |
| 1990 | 5.26 | 26 |
| 1989 | 7.13 | 16 |
| 1988 | 7.53 | 25 |
| 1987 | 3.4 | 49 |
| 1986 | 2.16 | 75 |