| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 51.81 | 81 |
| 2015 | 51.64 | 82 |
| 2014 | 51.7 | 85 |
| 2013 | 51.78 | 91 |
| 2012 | 51.97 | 92 |
| 2011 | 52.35 | 93 |
| 2010 | 52.99 | 97 |
| 2009 | 53.61 | 98 |
| 2008 | 54.48 | 101 |
| 2007 | 55.52 | 102 |
| 2006 | 56.56 | 101 |
| 2005 | 57.49 | 99 |
| 2004 | 58.54 | 99 |
| 2003 | 59.52 | 100 |
| 2002 | 60.53 | 100 |
| 2001 | 61.77 | 102 |
| 2000 | 63.38 | 101 |
| 1999 | 64.95 | 99 |
| 1998 | 66.78 | 103 |
| 1997 | 68.72 | 105 |
| 1996 | 70.47 | 105 |
| 1995 | 71.83 | 107 |
| 1994 | 73.3 | 105 |
| 1993 | 74.42 | 105 |
| 1992 | 75.29 | 105 |
| 1991 | 76.19 | 106 |
| 1990 | 77.33 | 106 |
| 1989 | 78.25 | 106 |
| 1988 | 79.24 | 106 |
| 1987 | 80.24 | 107 |
| 1986 | 81.11 | 108 |