| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 99.32 | 10 |
| 2015 | 99.24 | 10 |
| 2014 | 99.16 | 8 |
| 2013 | 99.06 | 8 |
| 2012 | 98.95 | 8 |
| 2011 | 98.81 | 8 |
| 2010 | 98.66 | 8 |
| 2009 | 98.47 | 8 |
| 2008 | 98.26 | 8 |
| 2007 | 98.02 | 9 |
| 2006 | 97.75 | 9 |
| 2005 | 97.45 | 9 |
| 2004 | 97.11 | 10 |
| 2003 | 96.87 | 10 |
| 2002 | 96.69 | 10 |
| 2001 | 96.51 | 10 |
| 2000 | 96.31 | 10 |
| 1999 | 96.11 | 10 |
| 1998 | 95.89 | 10 |
| 1997 | 95.66 | 10 |
| 1996 | 95.36 | 10 |
| 1995 | 95 | 10 |
| 1994 | 94.61 | 10 |
| 1993 | 94.2 | 10 |
| 1992 | 93.76 | 11 |
| 1991 | 93.29 | 11 |
| 1990 | 92.79 | 12 |
| 1989 | 92.25 | 11 |
| 1988 | 91.67 | 11 |
| 1987 | 91.06 | 12 |
| 1986 | 90.4 | 12 |