National Trends in Sulfur_Dioxide Concentrations in 1990 - 2010
Year Mean Number of Trend Sites 10th Percentile 90th Percentile
1990 7.63521283899308 229 1.1726706527155 14.2328950898846
1991 7.54975096363775 229 1.14032848343942 14.3779402803169
1992 6.98439656516519 229 1.09935097353969 13.0850117096019
1993 6.97253971508042 229 1.3202178030303 12.6689933872153
1994 6.76492876934643 229 1.34972883753832 12.5258713136729
1995 5.34581936960326 229 0.98229532898041 10.819749032485
1996 5.26932146805006 229 1.10799041713641 10.0911703839963
1997 5.19794362011175 229 1.27270631627478 9.53104007412555
1998 5.06919019758974 229 1.19800898385334 9.61075835629568
1999 4.92489545285576 229 1.30268691588785 9.0713954028326
2000 4.72807358104146 229 1.27060068179147 8.66614514381995
2001 4.3920315881627 229 1.13261772853186 8.03576127257505
2002 4.12869699760683 229 1.01157820573039 7.98927706675891
2003 4.1076901554178 229 0.96930299747201 8.21220896559713
2004 3.90435150250903 229 0.98281583313581 7.26256077795786
2005 4.0111736683729 229 0.96664019062748 7.48055623923209
2006 3.50773602013192 229 0.71855719031798 6.90059433632444
2007 3.36322507289676 229 0.78172892720306 6.44809004909592
2008 2.97984469409122 229 0.75424701561065 6.09350529709811
2009 2.41681499210024 229 0.51735233279705 5.24290697674419
2010 2.25828177249727 229 0.46184095543256 4.72094090648308