YEAR,Jan,Feb,Mar,Apr,May,Jun,Jul,Aug,Sep,Oct,Nov,Dec,Annual 24-hr Avg.
2004,,,,,21871,23850,25042,24525,22748,21423,19968,19899
2005,16081,19016,19986,20964,22078,23794,25387,27558,25254,21053,20274,  ,20120
2006,17714,18838,19852,20965,23023,24081,24656,24697,22673,21594,19563,18985,21387
2007,16934,18719,20315,20783,22535,26360,24468,24798,22272,21328,19740,16813,21255
2008,13515,15606,17667,19066,21189,21916,23361