National Trends in Nitrogen_Dioxide Concentrations in 1990 - 2008

Year	Mean	Number of Trend Sites	10th Percentile	90th Percentile
1990	0.02001986754966	151	0.0073	0.0352
1991	0.01979370860927	151	0.0076	0.0351
1992	0.01918973509933	151	0.0072	0.0345
1993	0.01910883002207	151	0.0074	0.0339
1994	0.01990971302428	151	0.0081	0.0346
1995	0.01899827814569	151	0.0072	0.0326
1996	0.01867185430463	151	0.0069	0.0327
1997	0.0179894039735	151	0.007	0.0318
1998	0.01782218543046	151	0.006	0.0322
1999	0.01854668874172	151	0.007	0.0317
2000	0.01750894039735	151	0.0068	0.0292
2001	0.01728476821192	151	0.0067	0.0297
2002	0.01662251655629	151	0.0064	0.0285
2003	0.01604668874172	151	0.0063	0.0275
2004	0.01486015452538	151	0.006	0.025
2005	0.01468057395143	151	0.0061	0.0243
2006	0.0139	151	0.0055	0.0228
2007	0.01340993377483	151	0.005	0.0223
2008	0.01251920529801	151	0.0046	0.0206