Year,Jan.,Feb.,Mar.,Apr.,May.,Jun.,Jul.,Aug.,Sep.,Oct.,Nov.,Dec.,24-Hour Annual Avg., 1990,8275,8923,9895,9969,10319,10475,10058,10629,10282,10175,9264,8147,9704, 1991,8023,9097,9762,10535,10525,10910,10175,10737,10489,10483,9381,8818,9913, 1992,9029,9786,10613,10813,10677,11077,11329,11094,10989,10514,9599,9313,10432, 1993,8623,9370,10074,11445,11487,11987,11773,11836,11776,11621,11192,10855,11010, 1994,9772,10412,11537,11302,11262,11821,11438,12090,12105,11691,11000,10157,11219, 1995,10475,11055,11546,12469,12390,12748,12274,12485,12083,12150,10597,10128,11700, 1996,10427,10971,11729,12193,12226,12564,12273,12618,12601,12222,11351,10035,11768, 1997,10201,11458,12203,12251,12337,13196,12607,12957,12888,12169,11662,11035,12080, 1998,10582,11497,12300,12679,12647,13042,12498,12904,12632,12449,11843,11251,12194, 1999,11041,11327,12490,12729,13075,12865,12668,12972,12502,12340,12114,10985,12259, 2000,10635,11674,12153,12922,12985,13137,,12580,12637,12296,11408,10748,, 2001,10385,11113,12205,12714,12776,13087,12717,13010,12903,12498,11692,10791,12158, 2002,11131,11848,12338,13454,13582,13770,12874,13246,13186,13435,12227,11375,12706, 2003,11659,12247,11619,,,,,,,,,,, 2004,,,13065,13031,12541,13123,12623,12952,13057,12657,12133,11863,, 2005,11274,12358,12954,13154,13056,13764,13401,14039,13338,13072,12343,11670,12869, 2006,11833,12654,13589,14235,14425,14425,13660,14511,14240,14332,13507,12481,13658, 2007,12535,13095,13989,13883,13795,12919,12290,13084,13159,13080,12226,11557,12968, 2008,11082,12358,12882,13604,13368,12686,11991,12283,12582,12600,11665,11403,12375, 2009,11057,12096,12482,13137,11596,11996,11839,12178,12363,11723,11532,11045,11920, 2010,10818,11928,12591,12717,12113,12419,12200,12387,12487,12254,11671,11040,12052, 2011,11034,11478,11755,12210,11800,11832,11767,11995,11882,11899,11601,11517,11731, 2012,11139,11647,12015,12684,12370,12731,12290,10650,11546,12395,11965,11501,11911, 2013,11208,12347,13229,13456,13165,12981,11456,12598,13362,,13585,12235,, 2014,12243,12728,13870,14367,14581,14957,14566,14475,14547,14403,13060,13099,13908, 2015,12811,14232,15022,15603,15569,16332,15845,15790,15672,15388,13919,13559,14978, 2016,13481,14697,15608,16414,16578,16876,16360,16562,16337,16431,15533,13621,15708, 2017,12207,14823,16402,17164,18092,17820,17327,17813,17408,17762,16745,15554,16593, 2018,15143,15940,16870,17786,17466,16896,17271,17547,17545,17359,16423,15605,16821, 2019,15621,15642,17169,18705,19353,19889,18950,19603,19496,19328,18129,17081,18247, 2020,16363,17549,16796,15362,17334,18655,18144,18472,18340,18528,16660,16153,17363, 2021,16424,16843,18756,19258,19234,19646,19085,18776,19067,19200,18088,16779,18430, 2022,16719,18321,19216,19659,19696,19777,19386,19404,19001,19607,17710,16440,18745, 2023,17010,18181,18553,20258,20702,20735,19926,20264,19922,19977,18634,17858,19335, 2024,16226,18638, , , , , , , , , , , ,