| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 18.04 | 35 |
| 2015 | 17.49 | 44 |
| 2014 | 15.43 | 55 |
| 2013 | 15.66 | 54 |
| 2012 | 15.64 | 52 |
| 2011 | 14.66 | 55 |
| 2010 | 17.48 | 51 |
| 2009 | 17.33 | 51 |
| 2008 | 15.95 | 53 |
| 2007 | 13.77 | 57 |
| 2006 | 14.96 | 58 |
| 2005 | 16.81 | 57 |
| 2004 | 15.65 | 59 |
| 2003 | 17.21 | 56 |
| 2002 | 15.53 | 56 |
| 2001 | 18.51 | 55 |
| 2000 | 19.14 | 55 |
| 1999 | 18.98 | 58 |
| 1998 | 19.37 | 55 |
| 1997 | 19.77 | 56 |
| 1996 | 19.92 | 57 |
| 1995 | 21.01 | 53 |
| 1994 | 18.98 | 61 |
| 1993 | 20.58 | 54 |
| 1992 | 18.61 | 59 |
| 1991 | 20.28 | 55 |
| 1990 | 19.93 | 59 |
| 1989 | 22.61 | 49 |
| 1988 | 21.17 | 49 |
| 1987 | 24.87 | 40 |
| 1986 | 24.14 | 39 |