| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 32.34 | 73 |
| 2015 | 32.3 | 72 |
| 2014 | 32.72 | 73 |
| 2013 | 33.24 | 76 |
| 2012 | 33.95 | 77 |
| 2011 | 34.98 | 79 |
| 2010 | 36.36 | 82 |
| 2009 | 38.11 | 86 |
| 2008 | 40.29 | 87 |
| 2007 | 42.91 | 93 |
| 2006 | 45.91 | 98 |
| 2005 | 49.2 | 105 |
| 2004 | 53.04 | 110 |
| 2003 | 57.4 | 116 |
| 2002 | 62.27 | 121 |
| 2001 | 67.59 | 124 |
| 2000 | 73.31 | 134 |
| 1999 | 77.42 | 145 |
| 1998 | 81.52 | 149 |
| 1997 | 85.44 | 162 |
| 1996 | 88.99 | 171 |
| 1995 | 92.07 | 179 |
| 1994 | 94.05 | 180 |
| 1993 | 95.21 | 181 |
| 1992 | 95.67 | 180 |
| 1991 | 95.73 | 181 |
| 1990 | 95.61 | 182 |
| 1989 | 95.16 | 179 |
| 1988 | 94.58 | 178 |
| 1987 | 93.82 | 177 |
| 1986 | 92.57 | 172 |