| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 55.53 | 66 |
| 2015 | 53.31 | 77 |
| 2014 | 48.21 | 83 |
| 2013 | 51.13 | 79 |
| 2012 | 44.58 | 88 |
| 2011 | 45.03 | 86 |
| 2010 | 43.28 | 93 |
| 2009 | 39.67 | 98 |
| 2008 | 36.52 | 100 |
| 2007 | 37.5 | 103 |
| 2006 | 32.55 | 108 |
| 2005 | 27.16 | 117 |
| 2004 | 28.86 | 110 |
| 2003 | 25.4 | 120 |
| 2002 | 21.23 | 127 |
| 2001 | 22.96 | 118 |
| 2000 | 26.75 | 101 |
| 1999 | 22.02 | 111 |
| 1998 | 21.06 | 115 |
| 1997 | 22.52 | 108 |
| 1996 | 24.97 | 99 |
| 1995 | 30.58 | 85 |
| 1994 | 29.96 | 88 |
| 1993 | 32.44 | 81 |
| 1992 | 30.17 | 84 |
| 1991 | 36.47 | 61 |
| 1990 | 36.05 | 59 |
| 1989 | 33.81 | 66 |
| 1988 | 35.14 | 58 |
| 1987 | 43.64 | 46 |
| 1986 | 45.04 | 38 |