Year,Jan.,Feb.,Mar.,Apr.,May.,Jun.,Jul.,Aug.,Sep.,Oct.,Nov.,Dec.,24-Hour Annual Avg., 1990,14203,14947,16112,16082,16099,16505,15895,16452,14861,15177,15885,17791,15841, 1991,13644,14897,15528,15819,16270,16344,16367,14811,11701,13929,15614,17293,15191, 1992,14601,15555,15796,16452,16366,16128,16242,16468,15692,15950,15707,17761,16107, 1993,14402,15547,16407,16830,17019,17472,17530,17635,17013,17280,17213,19174,16970, 1994,16224,17522,17691,17670,17816,18363,18368,18734,17519,17812,18023,20114,17993, 1995,,,,,,18347,17429,18348,17523,17823,18632,20443,, 1996,16748,18390,18535,18554,18751,19042,18240,18745,18169,17882,18237,19386,18390, 1997,16383,17643,17943,18180,18587,18734,18510,18849,17669,18123,18545,20377,18295, 1998,17395,18143,18740,18913,19496,19671,19380,19811,18635,19044,19274,20837,19112, 1999,17860,18771,19233,19648,20166,20498,20026,20303,19435,19639,19575,21153,19692, 2000,17815,18993,19110,19489,19539,19988,20795,22736,21006,19970,19669,21091,20017, 2001,17768,18736,19339,18728,19127,19553,19572,19892,18397,18446,19251,20043,19071, 2002,17382,18405,18799,18625,18874,18412,18475,19479,17842,18246,18798,20137,18623, 2003,17478,17567,16711,17336,17889,17916,17423,17715,17410,18906,18733,20170,17938, 2004,17884,18029,19089,19249,18855,19360,19326,19121,17731,18075,18433,20416,18797, 2005,16814,18249,18310,18507,18786,19036,18910,19416,17433,17549,17980,20192,18432, 2006,17094,18137,18792,19167,19520,19818,19257,19243,18103,18903,19791,21464,19107, 2007,18384,19591,20401,20194,20754,20863,20553,21444,20048,20436,20612,21741,20418, 2008,18797,20076,20460,21189,21959,21689,21333,21244,20319,21445,21790,22746,21087, 2009,20464,21489,21279,23179,23439,22249,22141,22112,20693,22371,21284,23046,21979, 2010,20086,21510,21644,23974,21452,22187,21317,21516,20523,21053,20560,23063,21574, 2011,19924,20985,21178,21674,22192,23240,20850,22481,21003,21416,21338,23174,21621, 2012,20296,21260,21389,21971,22435,22349,21599,22508,21009,21496,21413,22481,21684, 2013,19493,20957,21995,21819,22355,22103,21067,21640,20254,20637,20590,21792,21225, 2014,19547,20723,20971,21726,21761,21274,19623,19445,18698,19144,20200,22126,20436, 2015,19654,21344,21211,21658,21879,21688,21290,21901,21215,21869,21465,22575,21479, 2016,21590,22019,21621,22588,22830,,,21349,21394,22166,23326,22958,, 2017,19745,21943,22746,24039,25610,26106,25501,25914,24897,25239,24587,24879,24267, 2018,21381,22869,23049,23514,23593,24078,23930,24067,21670,22001,21958,22801,22909, 2019,20376,20764,22241,23135,23281,23373,22489,22887,22037,22356,22114,22243,22275, 2020,20326,21407,19594,16651,21467,22367,21680,21784,21036,21056,20529,21566,20789, 2021,20132,20463,22535,23213,23412,23704,22851,22825,22143,22663,21960,22603,22375, 2022,20356,21837,22205,22788,23289,23079,22285,22837,23520,23072,22267, ,22503, 2023,20763,21377,21398,23487,24475,23433,22488,23295,22136,22548,22183,23016,22550, 2024,20614,22014, , , , , , , , , , , ,