Year,Jan.,Feb.,Mar.,Apr.,May.,Jun.,Jul.,Aug.,Sep.,Oct.,Nov.,Dec.,24-Hour Annual Avg.,
1998,,,,,,,,,,17446,16114,15068,,
1999,15258,16355,16149,15107,13530,12756,12445,14032,14267,14827,12784,12321,14153,
2000,12000,13373,13190,14946,13333,12519,12281,13477,12362,14053,12251,11827,12968,
2001,11365,13161,12700,14416,13695,12465,12216,13946,14485,14621,12848,12364,13190,
2002,12136,13623,13018,15430,14287,12995,12805,14247,14993,15231,14123,13143,13836,
2003,12913,14370,13371,15678,14555,13504,13415,14795,15476,15880,13204,13231,14199,
2004,12459,14204,14053,16091,13978,13512,13132,15105,15628,16210,13823,13120,14276,
2005,13137,14572,14127,15728,14035,13379,12752,15123,14792,15133,13484,12287,14046,
2006,13171,14138,13858,15180,13819,12977,12006,14194,14200,14513,12784,11851,13558,
2007,12358,13307,13472,14586,12953,13304,,16876,16721,17112,15930,14079,,
2008,14299,16254,15918,18429,16396,15112,,14393,14756,15254,13749,12062,,
2009,12436,14227,13395,15589,14491,13750,13421,15214,15196,15930,15049,,,
2010,,,,,,,,,,,14533,13501,,
2011,14387,14386,14390,16062,14848,14119,13769,16247,16135,16327,14564,13604,14903,
2012,13093,14410,14154,15971,14346,13540,12768,15491,15514,15724,14470,12844,14360,
2013,13550,14772,14698,16389,14772,14227,13700,15772,15700,16150,12973,12208,14576,
2014,13365,14398,14816,16685,15341,14357,13862,15684,16031,16503,14537,13758,14945,
2015,13936,15721,15456,17341,15981,15057,14291,16531,16905,17225,15543,14193,15682,
2016,14937,16549,15834,17983,16284,15535,15065,17363,17601,17641,16510,13870,16264,
2017,14260,16271,16675,18347,16953,16004,15251,17096,17957,18319,16246,14713,16508,
2018,16070,16572,16918,19017,17047,16153,15513,18156,18256,18342,17129,14927,17008,
2019,16125,15363,17009,18555,16706,16194,15581,18161,18367,18374,17032,15520,16916,
2020, , ,13136,9331,11844,13506,13281,15066,14458,14618,12990,12056,13281,
2021,13460,13592,15249,16044,15537,15288,15129,17371,17473,18279,15915,16408,15812,
2022,14691,16376,16401,17743,16744,15463,15488,17827,18153,18372,15879,13985,16427,
2023,16079,17122,16994,18529,17230,16289,14664, ,18830,18942,16802,15424,16987,
2024,15583,17289,17403, , , , , , , , , , ,