| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 19.48 | 32 |
| 2015 | 19.66 | 38 |
| 2014 | 19.65 | 43 |
| 2013 | 19.74 | 45 |
| 2012 | 20.35 | 40 |
| 2011 | 29.59 | 17 |
| 2010 | 31.45 | 16 |
| 2009 | 35.04 | 13 |
| 2008 | 34.87 | 13 |
| 2007 | 36.06 | 9 |
| 2006 | 35.26 | 13 |
| 2005 | 36.18 | 15 |
| 2004 | 39.03 | 9 |
| 2003 | 41.03 | 8 |
| 2002 | 42.69 | 8 |
| 2001 | 43.96 | 7 |
| 2000 | 45.17 | 7 |
| 1999 | 53.71 | 4 |
| 1998 | 53.3 | 5 |
| 1997 | 52.8 | 6 |
| 1996 | 53.35 | 5 |
| 1995 | 55.68 | 4 |
| 1994 | 57.58 | 2 |
| 1993 | 57.54 | 3 |
| 1992 | 61.81 | 2 |
| 1991 | 58.23 | 2 |
| 1990 | 61.23 | 2 |
| 1989 | 60.55 | 2 |