National Trends in Carbon_Monoxide Concentrations in 1990 - 2008
| Year |
Mean |
Number of Trend Sites |
10th Percentile |
90th Percentile |
| 1990 |
6.02184466019417 |
206 |
3.3 |
9.2 |
| 1991 |
5.89708737864077 |
206 |
3.2 |
9.4 |
| 1992 |
5.47135922330097 |
206 |
3 |
8.2 |
| 1993 |
5.16553398058252 |
206 |
2.8 |
7.8 |
| 1994 |
5.33713592233009 |
206 |
2.8 |
7.9 |
| 1995 |
4.77912621359223 |
206 |
2.6 |
7.4 |
| 1996 |
4.44296116504854 |
206 |
2.4 |
6.8 |
| 1997 |
4.22936893203883 |
206 |
2.2 |
6.3 |
| 1998 |
4.0252427184466 |
206 |
2.2 |
6 |
| 1999 |
3.89635922330097 |
206 |
2.1 |
6 |
| 2000 |
3.51407766990291 |
206 |
1.8 |
5.5 |
| 2001 |
3.27669902912621 |
206 |
1.9 |
4.8 |
| 2002 |
2.96844660194174 |
206 |
1.6 |
4.5 |
| 2003 |
2.78446601941747 |
206 |
1.6 |
4.4 |
| 2004 |
2.57233009708737 |
206 |
1.4 |
3.9 |
| 2005 |
2.32014563106796 |
206 |
1.4 |
3.4 |
| 2006 |
2.21796116504854 |
206 |
1.3 |
3.3 |
| 2007 |
2 |
206 |
1.2 |
3 |
| 2008 |
1.88398058252427 |
206 |
1.1 |
2.8 |