| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 1.01 | 73 |
| 2015 | 1.1 | 68 |
| 2014 | 1.18 | 63 |
| 2013 | 1.21 | 63 |
| 2012 | 1.18 | 66 |
| 2011 | 1.1 | 70 |
| 2010 | 1 | 78 |
| 2009 | 0.91 | 85 |
| 2008 | 0.82 | 92 |
| 2007 | 0.75 | 96 |
| 2006 | 0.69 | 101 |
| 2005 | 0.64 | 102 |
| 2004 | 0.6 | 109 |
| 2003 | 0.57 | 110 |
| 2002 | 0.58 | 105 |
| 2001 | 0.64 | 96 |
| 2000 | 0.7 | 90 |
| 1999 | 0.77 | 93 |
| 1998 | 0.92 | 87 |
| 1997 | 1.16 | 77 |
| 1996 | 1.47 | 74 |
| 1995 | 2.12 | 43 |
| 1994 | 2.72 | 24 |
| 1993 | 2.96 | 21 |
| 1992 | 3.03 | 17 |
| 1991 | 2.97 | 19 |
| 1990 | 2.85 | 20 |
| 1989 | 2.89 | 19 |
| 1988 | 2.91 | 22 |
| 1987 | 2.87 | 24 |
| 1986 | 2.85 | 25 |