| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 98.36 | 11 |
| 2015 | 98.34 | 11 |
| 2014 | 98.33 | 9 |
| 2013 | 98.31 | 9 |
| 2012 | 98.29 | 9 |
| 2011 | 98.28 | 9 |
| 2010 | 98.26 | 9 |
| 2009 | 98.25 | 9 |
| 2008 | 98.23 | 9 |
| 2007 | 98.22 | 8 |
| 2006 | 98.2 | 8 |
| 2005 | 98.19 | 8 |
| 2004 | 98.17 | 8 |
| 2003 | 98.16 | 8 |
| 2002 | 98.14 | 8 |
| 2001 | 98.13 | 8 |
| 2000 | 98.11 | 8 |
| 1999 | 98.1 | 8 |
| 1998 | 98.09 | 8 |
| 1997 | 98.07 | 8 |
| 1996 | 98.06 | 8 |
| 1995 | 98.04 | 8 |
| 1994 | 98.03 | 8 |
| 1993 | 98.02 | 8 |
| 1992 | 98 | 8 |
| 1991 | 97.99 | 8 |
| 1990 | 97.97 | 8 |
| 1989 | 97.96 | 8 |
| 1988 | 97.95 | 8 |
| 1987 | 97.93 | 7 |
| 1986 | 97.92 | 7 |