Year,Jan.,Feb.,Mar.,Apr.,May.,Jun.,Jul.,Aug.,Sep.,Oct.,Nov.,Dec.,24-Hour Annual Avg., 1998,6919,7901,8598,9210,8448,7918,7183,7734,8814,9460,9193,8544,8327, 1999,7765,7971,9212,9818,9338,10537,10364,10265,9611,9220,9064,7923,9257, 2000,8219,8413,9167,9711,9486,9706,10091,9956,8896,8724,9344,8616,9194, 2001,10581,10921,9080,9290,9083,9714,9750,10008,9410,9615,9833,7902,9599, 2002,7817,8429,9445,9339,9961,10712,10411,10772,10359,10049,9381,7928,9550, 2003,,,,,,,,10489,9855,9540,8021,7112,, 2004,6844,7210,8287,8832,8303,9336,10036,10236,9507,9032,8037,7547,8601, 2005,,,,,,,,,,,,,, 2006,,,,,,,,,,,,,, 2007,,,,,,,,,,,,,, 2008,,,,,,,,,,,,,, 2009,,,,,,,,,,,,,, 2010,,,,,,,,,,,,,, 2011,,,,,,,,,,,,,, 2012,,,,,,,,,,,,,, 2013,,,,,,,,,,6603,6469,5953,, 2014,5699,5738,6648,6373,6587,6867,,7443,6805,6769,6431,5867,, 2015,6151,6948,7384,,7569,8260,8595,,8217,,6689,5666,, 2016,5383,6369,6784,6563,7026,7667,7791,7695,7200,6846,6653,5134,6759, 2017,4412,5281,6859,6713,6983,7275,7982,7671,6615,6237,6036,5314,6448, 2018,4930,5069,6233,6854,7138,,,,,,,,, 2019, , , , , , , , , , , , , , 2020, , , , , , , , , , , , , , 2021,6148,6142,7468,7696,8208,9706,9981,9440,8905,8210,7942,6681,8044, 2022,6002,6934,7599,7550,8127,9020,8899, , , , , ,7733, 2023, , , , ,8545,9228,9154,8866,8720,8103,7313,6772,8338, 2024,5835,7231,7580,8098,8332,9326,9360,8940,8449,7626,6045, , ,