| 年份 | 单位：% |
| 2011 | 7.83 |
| 2010 | 8.38 |
| 2009 | 8.85 |
| 2008 | 7.84 |
| 2007 | 8.60 |
| 2006 | 8.35 |
| 2005 | 8.60 |
| 2004 | 8.09 |
| 2003 | 7.83 |
| 2002 | 7.62 |
| 2001 | 6.98 |
| 2000 | 6.31 |
| 1999 | 6.61 |
| 1998 | 7.43 |
| 1997 | 7.82 |
| 1996 | 8.26 |
| 1995 | 8.72 |
| 1994 | 9.03 |
| 1993 | 8.82 |
| 1992 | 7.66 |
| 1991 | 6.10 |
| 1990 | 4.88 |
| 1989 | 4.38 |
| 1988 | 3.70 |
| 1987 | 2.28 |
| 1986 | 2.04 |
| 1985 | 3.21 |
前瞻产业研究院 咨询·服务