National Trends in Carbon_Monoxide Concentrations in 1980 - 2008
| Year |
Mean |
Number of Trend Sites |
10th Percentile |
90th Percentile |
| 1980 |
8.9508064516129 |
124 |
4.4 |
14.1 |
| 1981 |
8.78427419354838 |
124 |
3.9 |
13.6 |
| 1982 |
8.33682795698925 |
124 |
4.4 |
13.1 |
| 1983 |
8.29784946236559 |
124 |
4 |
12.6 |
| 1984 |
7.91895161290322 |
124 |
4.3 |
11.9 |
| 1985 |
7.35040322580645 |
124 |
3.9 |
11 |
| 1986 |
7.59354838709677 |
124 |
3.9 |
11.2 |
| 1987 |
6.87096774193548 |
124 |
3.8 |
9.6 |
| 1988 |
6.67620967741935 |
124 |
3.9 |
9.8 |
| 1989 |
6.7241935483871 |
124 |
3.7 |
9.9 |
| 1990 |
6.13037634408602 |
124 |
3.5 |
9.5 |
| 1991 |
5.89462365591397 |
124 |
3.3 |
8.9 |
| 1992 |
5.46935483870967 |
124 |
3.2 |
8 |
| 1993 |
5.2274193548387 |
124 |
2.9 |
7.6 |
| 1994 |
5.33790322580644 |
124 |
3.1 |
7.8 |
| 1995 |
4.79677419354838 |
124 |
2.7 |
7.3 |
| 1996 |
4.43467741935484 |
124 |
2.6 |
6.5 |
| 1997 |
4.20483870967741 |
124 |
2.4 |
6.1 |
| 1998 |
3.91370967741935 |
124 |
2.2 |
5.9 |
| 1999 |
3.93548387096774 |
124 |
2.2 |
5.7 |
| 2000 |
3.46129032258064 |
124 |
1.8 |
5.4 |
| 2001 |
3.28387096774193 |
124 |
2 |
4.8 |
| 2002 |
2.87741935483871 |
124 |
1.8 |
4.4 |
| 2003 |
2.69758064516129 |
124 |
1.7 |
3.8 |
| 2004 |
2.51129032258064 |
124 |
1.6 |
3.7 |
| 2005 |
2.29637096774193 |
124 |
1.4 |
3.3 |
| 2006 |
2.19516129032258 |
124 |
1.4 |
3.2 |
| 2007 |
2.02096774193548 |
124 |
1.2 |
3 |
| 2008 |
1.87419354838709 |
124 |
1.1 |
2.8 |