| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2014 | 12.81 | 117 |
| 2013 | 13.42 | 126 |
| 2012 | 14.5 | 117 |
| 2011 | 15.02 | 111 |
| 2010 | 14.65 | 113 |
| 2009 | 12.79 | 124 |
| 2008 | 14.45 | 113 |
| 2007 | 14.49 | 116 |
| 2006 | 14.93 | 106 |
| 2005 | 16.2 | 95 |
| 2004 | 15.62 | 97 |
| 2003 | 12.79 | 109 |
| 2002 | 13.55 | 103 |
| 2001 | 15.06 | 91 |
| 2000 | 13.68 | 91 |
| 1999 | 31.14 | 32 |
| 1998 | 26.96 | 37 |
| 1997 | 25.84 | 36 |
| 1996 | 21.04 | 49 |
| 1995 | 30.16 | 29 |
| 1994 | 38.36 | 25 |
| 1993 | 39.69 | 23 |
| 1992 | 19.85 | 46 |
| 1991 | 20.21 | 40 |
| 1990 | 21.44 | 36 |
| 1989 | 18.42 | 46 |
| 1988 | 15.91 | 54 |
| 1987 | 15.62 | 51 |
| 1986 | 14.7 | 52 |