Year,Jan.,Feb.,Mar.,Apr.,May.,Jun.,Jul.,Aug.,Sep.,Oct.,Nov.,Dec.,24-Hour Annual Avg.,
1990,23914,25259,26618,26206,26484,27638,27299,27385,26837,22546,23838,23123,25592,
1991,20204,23896,23889,25017,24616,24770,25377,24645,23660,23881,22055,22595,23714,
1992,21868,23048,23948,25788,25160,30591,24432,22302,22001,21768,20278,20407,23519,
1993,19205,18587,18686,19487,19947,20646,22512,22490,22052,21000,20627,21065,20539,
1994,20415,21200,21924,22256,21966,21970,19094,21830,22903,22408,21355,22405,21642,
1995,,,,24877,24609,26055,25180,25483,24640,23848,23515,23426,,
1996,22889,23946,24513,25393,25275,26290,24509,25388,24844,24462,24442,23568,24627,
1997,23110,24629,24718,25974,25949,25959,24774,24940,24234,24076,23424,23222,24584,
1998,22405,24007,24573,25908,25663,26933,25241,25490,25718,25549,22678,24152,24860,
1999,23340,24167,24896,25828,25909,26770,25155,25501,25419,24889,23748,23562,24932,
2000,23318,24686,25218,25833,25140,26191,24527,24643,24753,24359,23361,24048,24673,
2001,23242,24702,25343,26167,26125,26331,25044,26108,25252,24409,22178,21673,24715,
2002,21965,22860,22864,24979,25112,24781,24730,24573,23979,24132,22827,22568,23781,
2003,22814,23519,23175,24506,24360,25273,24019,23963,24432,24183,22054,22843,23762,
2004,21899,23041,24155,24785,23936,24761,23767,23745,24186,23695,23021,23180,23681,
2005,22430,23552,24247,24788,24134,23871,22710,23787,23122,22713,22425,22982,23397,
2006,22536,23527,23733,24044,24249,24281,,24367,24237,23755,23122,22597,,
2007,22693,23492,24246,24652,24811,24854,23781,24786,23699,24017,23115,21967,23843,
2008,21833,23333,22894,24355,24203,23473,22872,22492,23145,22790,21143,21636,22847,
2009,21140,22363,22175,23622,22129,21562,21575,22201,22491,21788,20653,21254,21913,
2010,20480,21646,22064,22321,21875,22455,,21778,21514,21522,21835,20252,,
2011,20059,21113,20800,21469,21289,21511,21591,22208,22425,21151,19987,,21208,
2012,20773,21976,22109,23131,23135,23237,22267,23097,23300,22946,21542,21337,22404,
2013,20332,22010,22533,23401,23339,23673,22441,22916,23025,22620,21152,20887,22361,
2014,20681,21696,22233,23346,23211,23281,22227,23011,23175,23076,20673,21470,22340,
2015,21051,22730,23038,24123,23719,23628,22983,23322,23526,23126,21854,21895,22916,
2016,21858,22887,23145,24293,24509,23506,22045,23053,23069,22778,20976,20947,22755,
2017,19904,21854,22595,23395,23463,23606,22597,23057,22866,22569,21658,20751,22360,
2018,20330,20161,20297,20044,20416,20690,19653,20854,20690,20864,20217,19939,20346,
2019,19846,20164,21108,22416,22203,22512,21823,22330,22474,21943,21106,21301,21602,
2020,21355,22517,18088,13160,16996,19358,18702,19652,19581,19691,17529,17195,18652,
2021,17517,18649,20425,21389,21910,22261,21792,22057,21730,21830,20869,22480,21076,
2022,19700,21248,19056,22447,22389,21981,21403,22549,22600,22590,20800,20506,21439,
2023,24763,25283,25331,26860,26823,25847,24392,25705,25228,25065,23795,23659,25229,
2024,22891,25402,25441, , , , , , , , , , ,