National Trends in Sulfur_Dioxide Concentrations in 1980 - 2010
Year Mean Number of Trend Sites 10th Percentile 90th Percentile
1980 11.830315980805 121 3.58789346246973 21.7646892655367
1981 11.3092515491042 121 3.19023009720684 19.5414459908856
1982 10.1016112309666 121 2.91642567958357 17.5305690661479
1983 9.66721086976661 121 3.04661748548109 16.6673957953579
1984 9.84301114241221 121 2.12353241449719 16.6254955779201
1985 9.46614710562968 121 1.96509962234666 16.9420166015625
1986 9.03438011171546 121 1.89428918590522 15.15625
1987 8.79388113288251 121 2.14754317847101 15.0565519679472
1988 9.19530446895797 121 2.21407095610343 15.2018121911038
1989 8.79477973808578 121 2.11569795719844 14.3602958169633
1990 8.30609205525857 121 1.802890310353 13.8004958092315
1991 8.17544900066018 121 1.59421992481203 13.7577169481654
1992 7.64383027963787 121 1.78235846840498 12.5067737079779
1993 7.62124415108452 121 2.05298707348317 12.5911487066323
1994 7.45514569941562 121 2.11604253351826 12.6222819447838
1995 5.9258390924234 121 1.73021913134759 10.8959009496334
1996 5.87625347689103 121 1.72137803039091 10.3589360835934
1997 5.79622995608203 121 1.9019931595707 9.40891234961945
1998 5.56904364217839 121 2.04519036887676 9.61075835629568
1999 5.27411274784538 121 1.98816051844467 8.97350053235538
2000 5.10243777267357 121 1.82313278008299 8.55232974910394
2001 4.78686310315687 121 1.48919552199948 8.03576127257505
2002 4.38606556693131 121 1.42849666361376 7.17575122292103
2003 4.31299642447088 121 1.30319518407039 8.02828985507246
2004 4.21762407428606 121 1.36200428724544 7.27722432153899
2005 4.29898051354881 121 1.50432106073162 7.26088987504379
2006 3.80712760461173 121 1.20958777211672 6.89627567003133
2007 3.66366046269669 121 0.95757864632983 6.44809004909592
2008 3.16088629544204 121 0.8379479803428 5.70974897840047
2009 2.52790865346998 121 0.57079152731326 4.41157444842324
2010 2.44287336732014 121 0.46184095543256 4.72094090648308