Year,Jan.,Feb.,Mar.,Apr.,May.,Jun.,Jul.,Aug.,Sep.,Oct.,Nov.,Dec.,24-Hour Annual Avg.,
1990,17106,18459,18608,18818,17204,18048,17541,18096,18179,18276,17940,15384,17795,
1991,16436,18045,17458,19514,17741,18667,18107,,,,,,,
1992,,16220,17650,18807,17075,18429,18723,18869,18956,19146,18164,17544,,
1993,17384,19444,19756,21187,19438,20247,19085,18918,21571,20943,19881,19023,19731,
1994,18778,21054,21878,22033,20512,20908,19241,20472,22413,21901,21240,19541,20820,
1995,20038,22193,22199,23155,21461,21867,19964,21305,23048,22915,21377,19841,21614,
1996,20093,22267,21864,23320,20556,20313,19072,20715,22725,21877,21134,17953,20991,
1997,18988,21562,21319,23039,21416,20822,19008,20039,22293,21741,20699,18802,20811,
1998,18219,20982,20535,21653,20239,20357,18691,20031,21882,21768,20339,18874,20298,
1999,20150,20962,20923,22282,21185,20809,20079,20844,22074,22155,20542,18908,20909,
2000,19170,21683,21426,22502,20670,20356,19070,20416,22297,22679,20961,19504,20895,
2001,19046,21306,21254,22330,19917,19520,18546,19611,20645,20894,19598,17651,20027,
2002,17967,19807,19162,21427,19346,18203,17359,18538,20259,20606,19303,18136,19176,
2003,18652,20039,19154,20950,19355,21371,18019,18726,21337,21107,18747,18239,19641,
2004,18241,20025,20616,21515,19253,18848,17680,18546,21986,20678,19663,18124,19598,
2005,18697,20446,20345,21329,19365,18779,17794,19848,20688,20384,19150,17666,19541,
2006,18020,20215,19971,20677,19471,18494,,,21167,20860,19390,17501,,
2007,18372,20423,20235,20971,19505,18750,17673,19191,20718,21768,19452,17541,19550,
2008,17053,19984,19314,21376,19821,17781,17436,18048,20418,20421,17938,17226,18901,
2009,16889,19536,18954,20803,18571,17782,17647,18035,20209,20032,17804,16832,18591,
2010,16586,19422,19685,20114,18506,17655,17280,21595,,19602,17718,16576,,
2011,16984,18830,18820,19598,18371,16931,16480,17970,19022,18308,16804,,18038,
2012,,,,,,,,,,,,,,
2013,,,,,,,14713,16496,18684,18464,16834,15733,,
2014,15433,17980,18013,19347,17670,16665,16091,17353,18677,18833,17461,16874,17533,
2015,16191,18336,18071,19246,17581,17463,16910,17669,19230,19018,17222,16428,17781,
2016,20255,21822,21221,22738,20663,19935,19253,20535,19535,18838,17232,15370,19783,
2017,15472,18220,18282,19438,17312,17209,15993,17515,18287,18744,17102,15954,17461,
2018,16965,17919,17844,19251,17651,17341,16764,17947,18457,19071,17385,15807,17700,
2019,16581,17840,18270,19532,18105,17685,16935,17713,18903,18904,17319,16465,17854,
2020,16364,18267,13178,8060,10628,12560,12363,13967,14362,14433,12476,11496,13179,
2021,12648,13703,15048,15086,15321,15561,14132,15983,16677,16612,14888,14326,14999,
2022,14362,16141,16155,16967,15861,15308,14684,16402,17181,18136, , ,16120,
2023, , , , , , , , , , , , , ,
2024, , , , , , , , , , , , , ,