| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 79.78 | 68 |
| 2015 | 76.38 | 93 |
| 2014 | 81.18 | 96 |
| 2013 | 80.02 | 106 |
| 2012 | 85.12 | 98 |
| 2011 | 83.43 | 102 |
| 2010 | 75.25 | 110 |
| 2009 | 67.92 | 121 |
| 2008 | 85.67 | 103 |
| 2007 | 78.49 | 115 |
| 2006 | 71.5 | 124 |
| 2005 | 67.91 | 130 |
| 2004 | 61.6 | 137 |
| 2003 | 58.33 | 138 |
| 2002 | 60.53 | 129 |
| 2001 | 59.42 | 126 |
| 2000 | 59.16 | 126 |
| 1999 | 53.99 | 124 |
| 1998 | 50.8 | 132 |
| 1997 | 51.15 | 133 |
| 1996 | 47.1 | 136 |
| 1995 | 51.72 | 129 |
| 1994 | 47.31 | 133 |
| 1993 | 49.67 | 116 |
| 1992 | 50.26 | 113 |
| 1991 | 49.78 | 109 |
| 1990 | 54.63 | 97 |
| 1989 | 50.35 | 90 |
| 1988 | 50.14 | 83 |
| 1987 | 49.66 | 83 |
| 1986 | 50.28 | 80 |