YEAR,Jan,Feb,Mar,Apr,May,Jun,Jul,Aug,Sep,Oct,Nov,Dec,Annual 24-hr Avg.
1990,17606,18135,18251,17671,16783,17590,17146,17792,16798,16436,17030,15519,17222
1991,16327,17345,16970,18569,17398,17740,18576,24501,29632,28728,28240,27786,21836
1992,29175,23893,19272,20298,18317,19904,18584,18209,20650,20591,19073,18681,20598
1993,18026,20499,20514,22170,20378,20857,19578,19598,21128,20302,19789,20371,20258
1994,19959,21598,22081,22149,20726,21587,19237,20752,22304,22034,21100,20010,21117
1995,20546,22216,22793,23268,21540,22196,20158,21477,22705,23121,21363,20161,21795
1996,20448,22321,22202,23363,19201,19350,18888,20416,22299,21759,21253,19149,20887
1997,19405,21692,21451,22892,21342,20788,19020,20290,22514,22329,21353,19631,21059
1998,19271,21864,21797,23159,20727,21107,19252,20495,21974,21952,20356,19475,20952
1999,19518,21272,21501,22603,20858,21076,19194,20618,21763,22083,20663,19347,20875
2000,19616,23587,23405,22618,20823,21599,19762,20100,21703,22145,20723,19623,21309
2001,19436,21493,21412,22482,20039,19923,18606,19861,20887,21145,20062,18231,20298
2002,18780,20359,19571,21499,19520,18681,17578,18687,20228,20793,19174,18294,19430
2003,18954,20243,19242,21098,19460,19524,18371,18763,21269,21282,18985,18583,19648
2004,18620,20283,20764,21681,19252,18921,17969,19302,21500,20891,19922,18493,19800
2005,19075,20655,20571,21478,19333,19284,18133,20635,,21144,19881,18428
2006,18851,21100,20702,21278,20579,19203,18186,22243,,,21652,18150
2007,19246,21151,20827,21602,21606,,18881,19811,17576,22467,20524,18429
2008,17927,20914,19800,21612,19743,18224,17474,18195,,19591,18182,17205
2009,16922,19597,18919,20666,18317,17620,17548