YEAR,Jan,Feb,Mar,Apr,May,Jun,Jul,Aug,Sep,Oct,Nov,Dec,Annual 24-hr Avg.
2001,,,,,15703,17888,17756,18583,18271,18522,18059,17534
2002,18135,18902,19201,20869,21110,20795,20713,21198,20749,21015,19809,19679,20181
2003,19862,20821,20301,21406,21175,21451,21215,20512,20866,20891,18912,19592,20584
2004,18830,19939,20970,21958,21198,21791,20758,20607,21021,20820,20380,20353,20719
2005,19778,21269,21568,21988,21643,22235,20417,21179,20500,20433,20328,20005,20945
2006,20198,20955,21192,21327,21993,22037,20233,21317,20555,20657,20257,19434,20846
2007,19971,20753,21131,21666,21859,21536,20540,21546,20553,21771,20568,19571,20955
2008,19755,20789,20442,21987,21558,20535,20219,20091,20693,21005,19807,19583,20539
2009,19476,20515,20399,22366,21675,21523,23055,22256,20955