National Trends in Carbon_Monoxide Concentrations in 1980 - 2014
| Year |
Mean |
Number of Trend Sites |
10th Percentile |
90th Percentile |
| 1980 |
9.09594594594595 |
74 |
4.6 |
12.9 |
| 1981 |
8.94932432432432 |
74 |
4.4 |
12.8 |
| 1982 |
8.45495495495495 |
74 |
4.9 |
12.9 |
| 1983 |
8.58018018018018 |
74 |
4.3 |
13.2 |
| 1984 |
7.99527027027027 |
74 |
4.6 |
11.9 |
| 1985 |
7.46148648648648 |
74 |
4.1 |
12.2 |
| 1986 |
7.80405405405405 |
74 |
4.5 |
11.2 |
| 1987 |
7.04864864864865 |
74 |
4.1 |
9.6 |
| 1988 |
6.94864864864865 |
74 |
4.25 |
10.3 |
| 1989 |
6.98108108108108 |
74 |
3.7 |
10.4 |
| 1990 |
6.54459459459459 |
74 |
3.5 |
10 |
| 1991 |
6.20135135135135 |
74 |
3.5 |
9.4 |
| 1992 |
5.6527027027027 |
74 |
3.3 |
8 |
| 1993 |
5.34864864864865 |
74 |
3.1 |
7.6 |
| 1994 |
5.5054054054054 |
74 |
3.2 |
8 |
| 1995 |
4.94729729729729 |
74 |
2.8 |
7.4 |
| 1996 |
4.58378378378378 |
74 |
2.8 |
6.9 |
| 1997 |
4.18783783783783 |
74 |
2.4 |
6.4 |
| 1998 |
4.09459459459459 |
74 |
2.4 |
5.9 |
| 1999 |
4.07567567567567 |
74 |
2.4 |
6.2 |
| 2000 |
3.56891891891891 |
74 |
2 |
5.4 |
| 2001 |
3.35135135135135 |
74 |
2 |
4.8 |
| 2002 |
2.90405405405405 |
74 |
1.8 |
4.4 |
| 2003 |
2.74594594594594 |
74 |
1.7 |
3.8 |
| 2004 |
2.54999999999999 |
74 |
1.6 |
3.6 |
| 2005 |
2.30472972972973 |
74 |
1.4 |
3.3 |
| 2006 |
2.24864864864864 |
74 |
1.3 |
3.3 |
| 2007 |
1.96621621621621 |
74 |
1.2 |
2.9 |
| 2008 |
1.74459459459459 |
74 |
1.1 |
2.5 |
| 2009 |
1.72027027027027 |
74 |
1 |
2.5 |
| 2010 |
1.62027027027027 |
74 |
0.9 |
2.3 |
| 2011 |
1.69459459459459 |
74 |
1 |
2.4 |
| 2012 |
1.54797297297297 |
74 |
0.9 |
2.1 |
| 2013 |
1.46216216216216 |
74 |
0.9 |
2.2 |
| 2014 |
1.40675675675675 |
74 |
0.8 |
2.2 |