National Trends in Nitrogen_Dioxide Concentrations in 2000 - 2012
Year Mean Number of Trend Sites 10th Percentile 90th Percentile
2000 58.3230366492146 191 33 84
2001 56.5230366492146 191 33 77
2002 55.0732984293193 191 29 81
2003 54.0150087260034 191 31 79
2004 50.7040139616056 191 29 73
2005 50.3476439790576 191 27 73
2006 49.0294938917975 191 27 68
2007 48.0621291448516 191 25 66.3333333333333
2008 47.344502617801 191 26 66
2009 43.3752181500872 191 24 61.5
2010 43.7828097731239 191 24 59.6
2011 43.1794938917975 191 22 60.55
2012 41.3350785340314 191 21 59