Year,Jan.,Feb.,Mar.,Apr.,May.,Jun.,Jul.,Aug.,Sep.,Oct.,Nov.,Dec.,24-Hour Annual Avg.,
1990,8561,9083,9479,9673,10423,10359,9901,9655,9474,9552,9111,8428,9476,
1991,8241,9050,9245,9880,10265,10162,10023,9722,11210,10919,9579,9577,9825,
1992,9340,9812,9976,10587,10856,11061,10410,10863,11463,10829,9718,10071,10444,
1993,9136,9880,10506,10948,11078,11520,11030,10757,11051,10728,9999,9983,10553,
1994,9605,9965,10755,11660,11161,11245,9909,10304,10652,10501,9822,9816,10449,
1995,9482,9998,10329,10799,11278,11322,10814,10964,10727,10731,10101,10215,10563,
1996,9380,10150,10605,11142,11758,12225,11511,11272,11639,11111,10957,10017,10981,
1997,10039,10564,10643,11603,12109,11961,11325,11317,11521,11397,10494,10258,11103,
1998,10072,10527,10679,11391,11757,11825,11546,11347,11226,11075,10443,10474,11030,
1999,9858,10243,10867,11206,11821,12004,11385,11189,11364,11261,10393,10228,10985,
2000,9823,10259,10479,11061,11368,11347,11085,10973,10862,10505,9997,9619,10615,
2001,9202,9833,10255,10527,10853,10960,11275,11135,11145,10799,10192,9833,10501,
2002,9656,9904,10255,10925,11996,11186,10861,10225,10386,10194,9712,9617,10410,
2003,9448,9550,9414,10441,11474,10512,10184,11097,12173,9956,8912,9597,10230,
2004,9034,9057,9764,10277,10373,10676,10058,10008,10079,9656,9231,9382,9800,
2005,8647,9316,9546,10195,10319,10475,9972,10261,10099,10016,9389,9275,9793,
2006,8761,9320,9519,9975,10528,9936,9578,10265,10288,,9235,9094,,
2007,8805,9275,9498,10194,10499,10133,9605,9639,10349,9593,8390,8991,9581,
2008,,9235,8957,9987,10255,8235,8086,8145,8334,9041,8426,8674,,
2009,8260,8724,8641,9760,10239,9381,9211,9192,,9608,8794,8786,,
2010,8464,9060,9116,9997,10665,,,,,,,,,
2011,,,,,,,,9682,9953,9769,8865,8941,,
2012,8597,8961,8890,9847,9958,9586,9247,9382,9621,9401,8680,8520,9224,
2013,7951,8672,8888,10095,10326,10122,9721,9820,10354,9913,9007,8826,9475,
2014,8582,9172,9264,10146,10240,9964,9685,10122,9794,10243,8855,8878,9579,
2015,8595,9270,9281,10186,9951,10051,9265,9539,10067,10205,9148,9031,9549,
2016,8688,9428,9422,10431,10598,11043,11080,10347,10225,10021,9435,9044,9980,
2017,8536,9360,9690,10519,10710,10241,9830,9962,10225,10045,9373,9138,9802,
2018,8980,9438,9363,10457,10388,9866,9498,9837,10126,9830,9348,9116,9687,
2019,8722,9093,9466,10410,10468,10345,9667,9967,10395,9942,9525,9149,9763,
2020,8901,9392,8397,7488,8973,9629,9523,9404,9731,9314,8533,8547,8986,
2021,8582,8830,9500,10349,10437,10097,9597,9709,10036,9834,9180,9000,9596,
2022,8596,9201,9260,10139,10413,9591,9337,9930,10840,10336,9030,8886,9630,
2023,8851,9313,9232,10238,11257,10484,10135,10301,10532,10413,9894,9500,10013,
2024,8992,9588,9515, , , , , , , , , , ,